diff --git a/package-lock.json b/package-lock.json
index 6cd39e9b74..b01b75f536 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -3008,6 +3008,15 @@
         "check-error": "^1.0.2"
       }
     },
+    "chai-moment": {
+      "version": "0.1.0",
+      "resolved": "https://registry.npmjs.org/chai-moment/-/chai-moment-0.1.0.tgz",
+      "integrity": "sha1-SpFoDPo6dc/aGEULK6tltIyQJAE=",
+      "dev": true,
+      "requires": {
+        "moment": "^2.10.6"
+      }
+    },
     "chalk": {
       "version": "4.1.0",
       "resolved": "https://registry.npmjs.org/chalk/-/chalk-4.1.0.tgz",
diff --git a/package.json b/package.json
index ff35d35ca2..fa504fbe82 100644
--- a/package.json
+++ b/package.json
@@ -112,6 +112,7 @@
     "axios": "^0.19.2",
     "chai": "^4.1.2",
     "chai-as-promised": "^7.1.1",
+    "chai-moment": "^0.1.0",
     "chalk": "^4.1.0",
     "cross-spawn": "^7.0.3",
     "expect.js": "^0.3.1",
diff --git a/test/api/unit/libs/cron.test.js b/test/api/unit/libs/cron.test.js
index 1544a8c373..ee0271d82f 100644
--- a/test/api/unit/libs/cron.test.js
+++ b/test/api/unit/libs/cron.test.js
@@ -42,13 +42,13 @@ describe('cron', () => {
   });
 
   it('updates user.preferences.timezoneOffsetAtLastCron', () => {
-    const timezoneOffsetFromUserPrefs = 1;
+    const timezoneUtcOffsetFromUserPrefs = -1;
 
     cron({
-      user, tasksByType, daysMissed, analytics, timezoneOffsetFromUserPrefs,
+      user, tasksByType, daysMissed, analytics, timezoneUtcOffsetFromUserPrefs,
     });
 
-    expect(user.preferences.timezoneOffsetAtLastCron).to.equal(timezoneOffsetFromUserPrefs);
+    expect(user.preferences.timezoneOffsetAtLastCron).to.equal(1);
   });
 
   it('resets user.items.lastDrop.count', () => {
@@ -240,7 +240,7 @@ describe('cron', () => {
       user1.purchased.plan.consecutive.gemCapExtra = 0;
 
       it('does not increment consecutive benefits after the first month', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(1, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(1, 'months')
           .add(2, 'days')
           .toDate());
         // Add 1 month to simulate what happens a month after the subscription was created.
@@ -256,7 +256,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits after the second month', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(2, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(2, 'months')
           .add(2, 'days')
           .toDate());
         // Add 1 month to simulate what happens a month after the subscription was created.
@@ -272,7 +272,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits after the third month', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(3, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(3, 'months')
           .add(2, 'days')
           .toDate());
         // Add 1 month to simulate what happens a month after the subscription was created.
@@ -288,7 +288,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits after the fourth month', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(4, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(4, 'months')
           .add(2, 'days')
           .toDate());
         // Add 1 month to simulate what happens a month after the subscription was created.
@@ -304,7 +304,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits correctly if user has been absent with continuous subscription', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(10, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(10, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -339,7 +339,7 @@ describe('cron', () => {
       user3.purchased.plan.consecutive.gemCapExtra = 5;
 
       it('does not increment consecutive benefits in the first month of the first paid period that they already have benefits for', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(1, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(1, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -352,7 +352,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the middle of the period that they already have benefits for', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(2, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(2, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -365,7 +365,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the final month of the period that they already have benefits for', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(3, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(3, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -378,7 +378,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits the month after the second paid period has started', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(4, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(4, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -391,7 +391,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the second month of the second period that they already have benefits for', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(5, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(5, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -404,7 +404,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the final month of the second period that they already have benefits for', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(6, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(6, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -417,7 +417,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits the month after the third paid period has started', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(7, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(7, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -430,7 +430,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits correctly if user has been absent with continuous subscription', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(10, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(10, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -465,7 +465,7 @@ describe('cron', () => {
       user6.purchased.plan.consecutive.gemCapExtra = 10;
 
       it('does not increment consecutive benefits in the first month of the first paid period that they already have benefits for', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(1, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(1, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -478,7 +478,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the final month of the period that they already have benefits for', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(6, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(6, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -491,7 +491,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits the month after the second paid period has started', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(7, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(7, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -504,7 +504,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits the month after the third paid period has started', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(13, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(13, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -517,7 +517,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits correctly if user has been absent with continuous subscription', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(19, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(19, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -552,7 +552,7 @@ describe('cron', () => {
       user12.purchased.plan.consecutive.gemCapExtra = 20;
 
       it('does not increment consecutive benefits in the first month of the first paid period that they already have benefits for', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(1, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(1, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -565,7 +565,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the final month of the period that they already have benefits for', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(12, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(12, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -578,7 +578,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits the month after the second paid period has started', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(13, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(13, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -591,7 +591,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits the month after the third paid period has started', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(25, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(25, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -604,7 +604,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits correctly if user has been absent with continuous subscription', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(37, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(37, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -641,7 +641,7 @@ describe('cron', () => {
       user3g.purchased.plan.consecutive.gemCapExtra = 5;
 
       it('does not increment consecutive benefits in the first month of the gift subscription', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(1, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(1, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -654,7 +654,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the second month of the gift subscription', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(2, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(2, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -667,7 +667,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the third month of the gift subscription', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(3, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(3, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -680,7 +680,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the month after the gift subscription has ended', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(4, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(4, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -717,7 +717,7 @@ describe('cron', () => {
       user6x.purchased.plan.consecutive.gemCapExtra = 15;
 
       it('increments consecutive benefits in the first month since the fix for #4819 goes live', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(1, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(1, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -730,7 +730,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the second month after the fix goes live', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(2, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(2, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -743,7 +743,7 @@ describe('cron', () => {
       });
 
       it('does not increment consecutive benefits in the third month after the fix goes live', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(3, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(3, 'months')
           .add(2, 'days')
           .toDate());
         cron({
@@ -756,7 +756,7 @@ describe('cron', () => {
       });
 
       it('increments consecutive benefits in the seventh month after the fix goes live', () => {
-        clock = sinon.useFakeTimers(moment().zone(0).startOf('month').add(7, 'months')
+        clock = sinon.useFakeTimers(moment().utcOffset(0).startOf('month').add(7, 'months')
           .add(2, 'days')
           .toDate());
         cron({
diff --git a/test/api/unit/libs/preening.test.js b/test/api/unit/libs/preening.test.js
index c2448c5df9..d458595fe2 100644
--- a/test/api/unit/libs/preening.test.js
+++ b/test/api/unit/libs/preening.test.js
@@ -9,7 +9,7 @@ describe('preenHistory', () => {
   beforeEach(() => {
     // Replace system clocks so we can get predictable results
     clock = sinon.useFakeTimers({
-      now: Number(moment('2013-10-20').zone(0).startOf('day').toDate()),
+      now: Number(moment('2013-10-20').utcOffset(0).startOf('day').toDate()),
       toFake: ['Date'],
     });
   });
diff --git a/test/api/unit/models/user.test.js b/test/api/unit/models/user.test.js
index 50c5f8cc8a..f3345e5478 100644
--- a/test/api/unit/models/user.test.js
+++ b/test/api/unit/models/user.test.js
@@ -761,7 +761,7 @@ describe('User Model', () => {
     });
   });
 
-  context('days missed', () => {
+  describe('daysUserHasMissed', () => {
     // http://forbrains.co.uk/international_tools/earth_timezones
     let user;
 
@@ -769,24 +769,51 @@ describe('User Model', () => {
       user = new User();
     });
 
-    it('should not cron early when going back a timezone', () => {
-      const yesterday = moment('2017-12-05T00:00:00.000-06:00'); // 11 pm on 4 Texas
-      const timezoneOffset = moment().zone('-06:00').zone();
-      user.lastCron = yesterday;
-      user.preferences.timezoneOffset = timezoneOffset;
+    it('correctly calculates days missed since lastCron', () => {
+      const now = moment();
+      user.lastCron = moment(now).subtract(5, 'days');
 
-      const today = moment('2017-12-06T00:00:00.000-06:00'); // 11 pm on 4 Texas
-      const req = {};
-      req.header = () => timezoneOffset + 60;
+      const { daysMissed } = user.daysUserHasMissed(now);
 
-      const { daysMissed } = user.daysUserHasMissed(today, req);
+      expect(daysMissed).to.eql(5);
+    });
 
+    it('uses timezone from preferences to calculate days missed', () => {
+      const now = moment('2017-07-08 01:00:00Z');
+      user.lastCron = moment('2017-07-04 13:00:00Z');
+      user.preferences.timezoneOffset = 120;
+
+      const { daysMissed } = user.daysUserHasMissed(now);
+
+      expect(daysMissed).to.eql(3);
+    });
+
+    it('uses timezone at last cron to calculate days missed', () => {
+      const now = moment('2017-09-08 13:00:00Z');
+      user.lastCron = moment('2017-09-06 01:00:00+02:00');
+      user.preferences.timezoneOffset = 0;
+      user.preferences.timezoneOffsetAtLastCron = -120;
+
+      const { daysMissed } = user.daysUserHasMissed(now);
+
+      expect(daysMissed).to.eql(2);
+    });
+
+    it('respects new timezone that drags time into same day', () => {
+      user.lastCron = moment('2017-12-05T00:00:00.000-06:00');
+      user.preferences.timezoneOffset = 360;
+      const today = moment('2017-12-06T00:00:00.000-06:00');
+      const requestWithMinus7Timezone = { header: () => 420 };
+
+      const { daysMissed } = user.daysUserHasMissed(today, requestWithMinus7Timezone);
+
+      expect(user.preferences.timezoneOffset).to.eql(420);
       expect(daysMissed).to.eql(0);
     });
 
     it('should not cron early when going back a timezone with a custom day start', () => {
       const yesterday = moment('2017-12-05T02:00:00.000-08:00');
-      const timezoneOffset = moment().zone('-08:00').zone();
+      const timezoneOffset = 480;
       user.lastCron = yesterday;
       user.preferences.timezoneOffset = timezoneOffset;
       user.preferences.dayStart = 2;
diff --git a/test/api/v3/integration/tasks/GET-tasks_user.test.js b/test/api/v3/integration/tasks/GET-tasks_user.test.js
index e82a09e00b..85602ded26 100644
--- a/test/api/v3/integration/tasks/GET-tasks_user.test.js
+++ b/test/api/v3/integration/tasks/GET-tasks_user.test.js
@@ -153,12 +153,12 @@ describe('GET /tasks/user', () => {
   });
 
   xit('returns dailies with isDue for the date specified and will add CDS offset if time is not supplied and assumes timezones', async () => {
-    const timezone = 420;
+    const timezoneOffset = 420;
     await user.update({
       'preferences.dayStart': 0,
-      'preferences.timezoneOffset': timezone,
+      'preferences.timezoneOffset': timezoneOffset,
     });
-    const startDate = moment().zone(timezone).subtract('4', 'days').startOf('day')
+    const startDate = moment().utcOffset(-timezoneOffset).subtract('4', 'days').startOf('day')
       .toISOString();
     await user.post('/tasks/user', [
       {
@@ -180,12 +180,12 @@ describe('GET /tasks/user', () => {
   });
 
   xit('returns dailies with isDue for the date specified and will add CDS offset if time is not supplied and assumes timezones', async () => {
-    const timezone = 240;
+    const timezoneOffset = 240;
     await user.update({
       'preferences.dayStart': 0,
-      'preferences.timezoneOffset': timezone,
+      'preferences.timezoneOffset': timezoneOffset,
     });
-    const startDate = moment().zone(timezone).subtract('4', 'days').startOf('day')
+    const startDate = moment().utcOffset(-timezoneOffset).subtract('4', 'days').startOf('day')
       .toISOString();
     await user.post('/tasks/user', [
       {
@@ -207,12 +207,12 @@ describe('GET /tasks/user', () => {
   });
 
   xit('returns dailies with isDue for the date specified and will add CDS offset if time is not supplied and assumes timezones', async () => {
-    const timezone = 540;
+    const timezoneOffset = 540;
     await user.update({
       'preferences.dayStart': 0,
-      'preferences.timezoneOffset': timezone,
+      'preferences.timezoneOffset': timezoneOffset,
     });
-    const startDate = moment().zone(timezone).subtract('4', 'days').startOf('day')
+    const startDate = moment().utcOffset(-timezoneOffset).subtract('4', 'days').startOf('day')
       .toISOString();
     await user.post('/tasks/user', [
       {
diff --git a/test/common/fns/getUtcOffset.test.js b/test/common/fns/getUtcOffset.test.js
new file mode 100644
index 0000000000..a91c886407
--- /dev/null
+++ b/test/common/fns/getUtcOffset.test.js
@@ -0,0 +1,25 @@
+import getUtcOffset from '../../../website/common/script/fns/getUtcOffset';
+
+describe('getUtcOffset', () => {
+  let user;
+
+  beforeEach(() => {
+    user = { preferences: {} };
+  });
+
+  it('returns 0 when user.timezoneOffset is not set', () => {
+    expect(getUtcOffset(user)).to.equal(0);
+  });
+
+  it('returns 0 when user.timezoneOffset is zero', () => {
+    user.preferences.timezoneOffset = 0;
+
+    expect(getUtcOffset(user)).to.equal(0);
+  });
+
+  it('returns the opposite of user.timezoneOffset', () => {
+    user.preferences.timezoneOffset = -10;
+
+    expect(getUtcOffset(user)).to.eql(10);
+  });
+});
diff --git a/test/common/libs/cron.test.js b/test/common/libs/cron.test.js
new file mode 100644
index 0000000000..0894a6afa3
--- /dev/null
+++ b/test/common/libs/cron.test.js
@@ -0,0 +1,184 @@
+import moment from 'moment';
+
+import { startOfDay, daysSince } from '../../../website/common/script/cron';
+
+function localMoment (timeString, utcOffset) {
+  return moment(timeString).utcOffset(utcOffset, true);
+}
+
+describe('cron utility functions', () => {
+  describe('startOfDay', () => {
+    it('is zero when no daystart configured', () => {
+      const options = { now: moment('2020-02-02 09:30:00Z'), timezoneOffset: 0 };
+
+      const result = startOfDay(options);
+
+      expect(result).to.be.sameMoment('2020-02-02 00:00:00Z');
+    });
+
+    it('is zero when negative daystart configured', () => {
+      const options = {
+        now: moment('2020-02-02 09:30:00Z'),
+        timezoneOffset: 0,
+        daystart: -5,
+      };
+
+      const result = startOfDay(options);
+
+      expect(result).to.be.sameMoment('2020-02-02 00:00:00Z');
+    });
+
+    it('is zero when daystart over 24 is configured', () => {
+      const options = {
+        now: moment('2020-02-02 09:30:00Z'),
+        timezoneOffset: 0,
+        daystart: 25,
+      };
+
+      const result = startOfDay(options);
+
+      expect(result).to.be.sameMoment('2020-02-02 00:00:00Z');
+    });
+
+    it('is equal to daystart o\'clock when daystart configured', () => {
+      const options = {
+        now: moment('2020-02-02 09:30:00Z'),
+        timezoneOffset: 0,
+        dayStart: 5,
+      };
+
+      const result = startOfDay(options);
+
+      expect(result).to.be.sameMoment('2020-02-02 05:00:00Z');
+    });
+
+    it('is previous day daystart o\'clock when daystart is after current time', () => {
+      const options = {
+        now: moment('2020-02-02 04:30:00Z'),
+        timezoneOffset: 0,
+        dayStart: 5,
+      };
+
+      const result = startOfDay(options);
+
+      expect(result).to.be.sameMoment('2020-02-01 05:00:00Z');
+    });
+
+    it('is daystart o\'clock when daystart is after current time due to timezone', () => {
+      const options = {
+        now: moment('2020-02-02 04:30:00Z'),
+        timezoneOffset: -120,
+        dayStart: 5,
+      };
+
+      const result = startOfDay(options);
+
+      expect(result).to.be.sameMoment('2020-02-02 05:00:00+02:00');
+    });
+
+    it('returns in default timezone if no timezone defined', () => {
+      const utcOffset = moment().utcOffset();
+      const now = localMoment('2020-02-02 04:30:00', utcOffset).utc();
+
+      const result = startOfDay({ now });
+
+      expect(result).to.be.sameMoment(localMoment('2020-02-02', utcOffset));
+    });
+
+    it('returns in default timezone if timezone lower than -12:00', () => {
+      const utcOffset = moment().utcOffset();
+      const options = {
+        now: localMoment('2020-02-02 17:30:00', utcOffset).utc(),
+        timezoneOffset: 721,
+      };
+
+      const result = startOfDay(options);
+
+      expect(result).to.be.sameMoment(localMoment('2020-02-02', utcOffset));
+    });
+
+    it('returns in default timezone if timezone higher than +14:00', () => {
+      const utcOffset = moment().utcOffset();
+      const options = {
+        now: localMoment('2020-02-02 07:32:25.376', utcOffset).utc(),
+        timezoneOffset: -841,
+      };
+
+      const result = startOfDay(options);
+
+      expect(result).to.be.sameMoment(localMoment('2020-02-02', utcOffset));
+    });
+
+    it('returns in overridden timezone if override present', () => {
+      const options = {
+        now: moment('2020-02-02 13:30:27Z'),
+        timezoneOffset: 0,
+        timezoneUtcOffsetOverride: -240,
+      };
+
+      const result = startOfDay(options);
+
+      expect(result).to.be.sameMoment('2020-02-02 00:00:00-04:00');
+    });
+
+    it('returns start of yesterday if timezone difference carries it over datelines', () => {
+      const offset = 300;
+      const options = {
+        now: moment('2020-02-02 04:30:00Z'),
+        timezoneOffset: offset,
+      };
+
+      const result = startOfDay(options);
+
+      expect(result).to.be.sameMoment(localMoment('2020-02-01', -offset));
+    });
+  });
+
+  describe('daysSince', () => {
+    it('correctly calculates days between two dates', () => {
+      const now = moment();
+      const dayBeforeYesterday = moment(now).subtract({ days: 2 });
+
+      expect(daysSince(dayBeforeYesterday, { now })).to.equal(2);
+    });
+
+    it('is one lower if current time is before dayStart', () => {
+      const oneWeekAgoAtOnePm = moment().hour(13).subtract({ days: 7 });
+      const thisMorningThreeAm = moment().hour(3);
+      const options = {
+        now: thisMorningThreeAm,
+        dayStart: 6,
+      };
+
+      const result = daysSince(oneWeekAgoAtOnePm, options);
+
+      expect(result).to.equal(6);
+    });
+
+    it('is one higher if reference time is before dayStart and current time after dayStart', () => {
+      const oneWeekAgoAtEightAm = moment().hour(8).subtract({ days: 7 });
+      const todayAtFivePm = moment().hour(17);
+      const options = {
+        now: todayAtFivePm,
+        dayStart: 11,
+      };
+
+      const result = daysSince(oneWeekAgoAtEightAm, options);
+
+      expect(result).to.equal(8);
+    });
+
+    // Variations in timezone configuration options are already covered by startOfDay tests.
+    it('uses now in user timezone as configured in options', () => {
+      const timezoneOffset = 120;
+      const options = {
+        now: moment('1989-11-09 02:53:00+01:00'),
+        timezoneOffset,
+      };
+
+      const result = daysSince(localMoment('1989-11-08', -timezoneOffset), options);
+
+      expect(result).to.equal(0);
+    });
+  });
+});
diff --git a/test/common/libs/taskDefaults.test.js b/test/common/libs/taskDefaults.test.js
index e69bafa45d..479a87fa30 100644
--- a/test/common/libs/taskDefaults.test.js
+++ b/test/common/libs/taskDefaults.test.js
@@ -1,6 +1,7 @@
 import moment from 'moment';
 
 import taskDefaults from '../../../website/common/script/libs/taskDefaults';
+import getUtcOffset from '../../../website/common/script/fns/getUtcOffset';
 import { generateUser } from '../../helpers/common.helper';
 
 describe('taskDefaults', () => {
@@ -72,7 +73,7 @@ describe('taskDefaults', () => {
 
     expect(task.startDate).to.eql(
       moment()
-        .zone(user.preferences.timezoneOffset, 'hour')
+        .utcOffset(getUtcOffset(user))
         .startOf('day')
         .subtract(1, 'day')
         .toDate(),
diff --git a/test/common/shouldDo.test.js b/test/common/shouldDo.test.js
index b8f9a604ad..d7250f871a 100644
--- a/test/common/shouldDo.test.js
+++ b/test/common/shouldDo.test.js
@@ -5,6 +5,8 @@ import 'moment-recur';
 describe('shouldDo', () => {
   let day; let
     dailyTask;
+  // Options is a mapping of user.preferences, therefor `timezoneOffset` still holds old zone
+  // values instead of utcOffset values.
   let options = {};
   let nextDue = [];
 
@@ -80,17 +82,17 @@ describe('shouldDo', () => {
 
       it('returns true if the user\'s current time is after start date and Custom Day Start', () => {
         options.dayStart = 4;
-        day = moment().zone(options.timezoneOffset).startOf('day').add(6, 'hours')
+        day = moment().utcOffset(-options.timezoneOffset).startOf('day').add(6, 'hours')
           .toDate();
-        dailyTask.startDate = moment().zone(options.timezoneOffset).startOf('day').toDate();
+        dailyTask.startDate = moment().utcOffset(-options.timezoneOffset).startOf('day').toDate();
         expect(shouldDo(day, dailyTask, options)).to.equal(true);
       });
 
       it('returns false if the user\'s current time is before Custom Day Start', () => {
         options.dayStart = 8;
-        day = moment().zone(options.timezoneOffset).startOf('day').add(2, 'hours')
+        day = moment().utcOffset(-options.timezoneOffset).startOf('day').add(2, 'hours')
           .toDate();
-        dailyTask.startDate = moment().zone(options.timezoneOffset).startOf('day').toDate();
+        dailyTask.startDate = moment().utcOffset(-options.timezoneOffset).startOf('day').toDate();
         expect(shouldDo(day, dailyTask, options)).to.equal(false);
       });
     });
@@ -112,14 +114,14 @@ describe('shouldDo', () => {
 
       it('returns true if the user\'s current time is after Custom Day Start', () => {
         options.dayStart = 4;
-        day = moment().zone(options.timezoneOffset).startOf('day').add(6, 'hours')
+        day = moment().utcOffset(-options.timezoneOffset).startOf('day').add(6, 'hours')
           .toDate();
         expect(shouldDo(day, dailyTask, options)).to.equal(true);
       });
 
       it('returns false if the user\'s current time is before Custom Day Start', () => {
         options.dayStart = 8;
-        day = moment().zone(options.timezoneOffset).startOf('day').add(2, 'hours')
+        day = moment().utcOffset(-options.timezoneOffset).startOf('day').add(2, 'hours')
           .toDate();
         expect(shouldDo(day, dailyTask, options)).to.equal(false);
       });
diff --git a/test/helpers/globals.helper.js b/test/helpers/globals.helper.js
index bca96eac2c..213efac698 100644
--- a/test/helpers/globals.helper.js
+++ b/test/helpers/globals.helper.js
@@ -8,8 +8,9 @@
 //------------------------------
 global._ = require('lodash');
 global.chai = require('chai');
-chai.use(require('sinon-chai'));
 chai.use(require('chai-as-promised'));
+chai.use(require('chai-moment'));
+chai.use(require('sinon-chai'));
 
 global.expect = chai.expect;
 global.sinon = require('sinon');
diff --git a/website/client/src/app.vue b/website/client/src/app.vue
index 08c79f349a..21d00e8c93 100644
--- a/website/client/src/app.vue
+++ b/website/client/src/app.vue
@@ -297,7 +297,7 @@ export default {
     };
   },
   computed: {
-    ...mapState(['isUserLoggedIn', 'browserTimezoneOffset', 'isUserLoaded', 'notificationsRemoved']),
+    ...mapState(['isUserLoggedIn', 'browserTimezoneUtcOffset', 'isUserLoaded', 'notificationsRemoved']),
     ...mapState({ user: 'user.data' }),
     isStaticPage () {
       return this.$route.meta.requiresLogin === false;
@@ -493,9 +493,10 @@ export default {
         this.hideLoadingScreen();
 
         // Adjust the timezone offset
-        if (this.user.preferences.timezoneOffset !== this.browserTimezoneOffset) {
+        const browserTimezoneOffset = -this.browserTimezoneUtcOffset;
+        if (this.user.preferences.timezoneOffset !== browserTimezoneOffset) {
           this.$store.dispatch('user:set', {
-            'preferences.timezoneOffset': this.browserTimezoneOffset,
+            'preferences.timezoneOffset': browserTimezoneOffset,
           });
         }
 
diff --git a/website/client/src/components/settings/site.vue b/website/client/src/components/settings/site.vue
index 6abe0d5279..cdd8ee79b2 100644
--- a/website/client/src/components/settings/site.vue
+++ b/website/client/src/components/settings/site.vue
@@ -559,6 +559,7 @@ import resetModal from './resetModal';
 import deleteModal from './deleteModal';
 import { SUPPORTED_SOCIAL_NETWORKS } from '@/../../common/script/constants';
 import changeClass from '@/../../common/script/ops/changeClass';
+import getUtcOffset from '@/../../common/script/fns/getUtcOffset';
 import notificationsMixin from '../../mixins/notifications';
 import sounds from '../../libs/sounds';
 import { buildAppleAuthUrl } from '../../libs/auth';
@@ -616,17 +617,8 @@ export default {
       return ['off', ...this.content.audioThemes];
     },
     timezoneOffsetToUtc () {
-      let offset = this.user.preferences.timezoneOffset;
-      const sign = offset > 0 ? '-' : '+';
-
-      offset = Math.abs(offset) / 60;
-
-      const hour = Math.floor(offset);
-
-      const minutesInt = (offset - hour) * 60;
-      const minutes = minutesInt < 10 ? `0${minutesInt}` : minutesInt;
-
-      return `UTC${sign}${hour}:${minutes}`;
+      const offsetString = moment().utcOffset(getUtcOffset(this.user)).format('Z');
+      return `UTC${offsetString}`;
     },
     dayStart () {
       return this.user.preferences.dayStart;
diff --git a/website/client/src/libs/auth.js b/website/client/src/libs/auth.js
index 917812f545..41ae06de45 100644
--- a/website/client/src/libs/auth.js
+++ b/website/client/src/libs/auth.js
@@ -8,13 +8,14 @@ export function setUpAxios (AUTH_SETTINGS) { // eslint-disable-line import/prefe
     AUTH_SETTINGS = JSON.parse(AUTH_SETTINGS); // eslint-disable-line no-param-reassign
   }
 
-  const browserTimezoneOffset = moment().zone();
+  const browserTimezoneUtcOffset = moment().utcOffset();
 
   if (AUTH_SETTINGS.auth && AUTH_SETTINGS.auth.apiId && AUTH_SETTINGS.auth.apiToken) {
     axios.defaults.headers.common['x-api-user'] = AUTH_SETTINGS.auth.apiId;
     axios.defaults.headers.common['x-api-key'] = AUTH_SETTINGS.auth.apiToken;
 
-    axios.defaults.headers.common['x-user-timezoneOffset'] = browserTimezoneOffset;
+    // Communicate in "old" timezone variant for backwards compatibility
+    axios.defaults.headers.common['x-user-timezoneOffset'] = -browserTimezoneUtcOffset;
 
     return true;
   }
diff --git a/website/client/src/store/index.js b/website/client/src/store/index.js
index 94405ae54f..8723b10ff7 100644
--- a/website/client/src/store/index.js
+++ b/website/client/src/store/index.js
@@ -17,8 +17,8 @@ const IS_TEST = process.env.NODE_ENV === 'test'; // eslint-disable-line no-proce
 // before trying to load data
 let isUserLoggedIn = false;
 
-// eg, 240 - this will be converted on server as -(offset/60)
-const browserTimezoneOffset = moment().zone();
+// eg, -240 - this will be converted on server as (offset/60)
+const browserTimezoneUtcOffset = moment().utcOffset();
 
 axios.defaults.headers.common['x-client'] = 'habitica-web';
 
@@ -71,7 +71,7 @@ export default function () {
       // store the timezone offset in case it's different than the one in
       // user.preferences.timezoneOffset and change it after the user is synced
       // in app.vue
-      browserTimezoneOffset,
+      browserTimezoneUtcOffset,
       tasks: asyncResourceFactory(), // user tasks
       // @TODO use asyncresource?
       completedTodosStatus: 'NOT_LOADED',
diff --git a/website/common/script/cron.js b/website/common/script/cron.js
index 8afca4bcda..1342e6b8d2 100644
--- a/website/common/script/cron.js
+++ b/website/common/script/cron.js
@@ -33,26 +33,29 @@ function sanitizeOptions (o) {
   const ref = Number(o.dayStart || 0);
   const dayStart = !Number.isNaN(ref) && ref >= 0 && ref <= 24 ? ref : 0;
 
-  let timezoneOffset;
-  const timezoneOffsetDefault = Number(moment().zone());
+  let timezoneUtcOffset;
+  const timezoneUtcOffsetDefault = moment().utcOffset();
 
-  if (Number.isFinite(o.timezoneOffsetOverride)) {
-    timezoneOffset = Number(o.timezoneOffsetOverride);
+  if (Number.isFinite(o.timezoneUtcOffset)) {
+    // Options were already sanitized
+    timezoneUtcOffset = o.timezoneUtcOffset;
+  } else if (Number.isFinite(o.timezoneUtcOffsetOverride)) {
+    timezoneUtcOffset = o.timezoneUtcOffsetOverride;
   } else if (Number.isFinite(o.timezoneOffset)) {
-    timezoneOffset = Number(o.timezoneOffset);
+    timezoneUtcOffset = -o.timezoneOffset;
   } else {
-    timezoneOffset = timezoneOffsetDefault;
+    timezoneUtcOffset = timezoneUtcOffsetDefault;
   }
-  if (timezoneOffset > 720 || timezoneOffset < -840) {
-    // timezones range from -12 (offset +720) to +14 (offset -840)
-    timezoneOffset = timezoneOffsetDefault;
+  if (timezoneUtcOffset < -720 || timezoneUtcOffset > 840) {
+    // timezones range from -12 (offset -720) to +14 (offset 840)
+    timezoneUtcOffset = timezoneUtcOffsetDefault;
   }
 
-  const now = o.now ? moment(o.now).zone(timezoneOffset) : moment().zone(timezoneOffset);
+  const now = moment(o.now).utcOffset(timezoneUtcOffset);
   // return a new object, we don't want to add "now" to user object
   return {
     dayStart,
-    timezoneOffset,
+    timezoneUtcOffset,
     now,
   };
 }
@@ -81,7 +84,7 @@ export function startOfDay (options = {}) {
   const o = sanitizeOptions(options);
   const dayStart = moment(o.now).startOf('day').add({ hours: o.dayStart });
 
-  if (moment(o.now).hour() < o.dayStart) {
+  if (o.now.hour() < o.dayStart) {
     dayStart.subtract({ days: 1 });
   }
 
@@ -119,7 +122,7 @@ export function shouldDo (day, dailyTask, options = {}) {
   // NB: The user's day start date has already been converted to the PREVIOUS
   // day's date if the time portion was before CDS.
 
-  const startDate = moment(dailyTask.startDate).zone(o.timezoneOffset).startOf('day');
+  const startDate = moment(dailyTask.startDate).utcOffset(o.timezoneUtcOffset).startOf('day');
 
   if (startDate > startOfDayWithCDSTime.startOf('day') && !options.nextDue) {
     return false; // Daily starts in the future
diff --git a/website/common/script/fns/getUtcOffset.js b/website/common/script/fns/getUtcOffset.js
new file mode 100644
index 0000000000..7f17f9a363
--- /dev/null
+++ b/website/common/script/fns/getUtcOffset.js
@@ -0,0 +1,12 @@
+/**
+ * Converts from timezoneOffset (which corresponded to the value returned
+ * from moment.js's deprecated `moment#zone` method) to timezoneUtcOffset.
+ *
+ * This is done with conversion instead of changing it in the database to
+ * be backwards compatible with the database values and old clients.
+ *
+ * Not as a user method since it needs to work in the frontend as well.
+ */
+export default function getUtcOffset (user) {
+  return -(user.preferences.timezoneOffset || 0);
+}
diff --git a/website/common/script/index.js b/website/common/script/index.js
index b2435c42d3..d3e05c26af 100644
--- a/website/common/script/index.js
+++ b/website/common/script/index.js
@@ -28,6 +28,7 @@ import apiErrors from './errors/apiErrorMessages';
 import commonErrors from './errors/commonErrorMessages';
 import autoAllocate from './fns/autoAllocate';
 import crit from './fns/crit';
+import getUtcOffset from './fns/getUtcOffset';
 import handleTwoHanded from './fns/handleTwoHanded';
 import predictableRandom from './fns/predictableRandom';
 import randomDrop from './fns/randomDrop';
@@ -151,6 +152,7 @@ api.fns = {
   resetGear,
   ultimateGear,
   updateStats,
+  getUtcOffset,
 };
 
 api.ops = {
diff --git a/website/common/script/libs/taskDefaults.js b/website/common/script/libs/taskDefaults.js
index 69ba53824b..d966626e0b 100644
--- a/website/common/script/libs/taskDefaults.js
+++ b/website/common/script/libs/taskDefaults.js
@@ -1,6 +1,7 @@
 import { v4 as uuid } from 'uuid';
 import defaults from 'lodash/defaults';
 import moment from 'moment';
+import getUtcOffset from '../fns/getUtcOffset';
 
 // Even though Mongoose handles task defaults,
 // we want to make sure defaults are set on the client-side before
@@ -66,7 +67,7 @@ export default function taskDefaults (task, user) {
   }
 
   if (task.type === 'daily') {
-    const now = moment().zone(user.preferences.timezoneOffset);
+    const now = moment().utcOffset(getUtcOffset(user));
     const startOfDay = now.clone().startOf('day');
     const startOfDayWithCDSTime = startOfDay
       .clone()
diff --git a/website/common/script/ops/scoreTask.js b/website/common/script/ops/scoreTask.js
index 1062d901e4..4bd3be7cae 100644
--- a/website/common/script/ops/scoreTask.js
+++ b/website/common/script/ops/scoreTask.js
@@ -8,6 +8,8 @@ import {
 import i18n from '../i18n';
 import updateStats from '../fns/updateStats';
 import crit from '../fns/crit';
+import getUtcOffset from '../fns/getUtcOffset';
+
 import statsComputed from '../libs/statsComputed';
 import { checkOnboardingStatus } from '../libs/onboarding';
 
@@ -194,14 +196,14 @@ function _lastHistoryEntryWasToday (lastHistoryEntry, user) {
     return false;
   }
 
-  const { timezoneOffset } = user.preferences;
+  const timezoneUtcOffset = getUtcOffset(user);
   const { dayStart } = user.preferences;
 
   // Adjust the last entry date according to the user's timezone and CDS
-  const dateWithTimeZone = moment(lastHistoryEntry.date).zone(timezoneOffset);
+  const dateWithTimeZone = moment(lastHistoryEntry.date).utcOffset(timezoneUtcOffset);
   if (dateWithTimeZone.hour() < dayStart) dateWithTimeZone.subtract(1, 'day');
 
-  return moment().zone(timezoneOffset).isSame(dateWithTimeZone, 'day');
+  return moment().utcOffset(timezoneUtcOffset).isSame(dateWithTimeZone, 'day');
 }
 
 function _updateLastHistoryEntry (lastHistoryEntry, task, direction, times) {
diff --git a/website/server/controllers/top-level/dataexport.js b/website/server/controllers/top-level/dataexport.js
index 9de16046ed..2a17f4e5e4 100644
--- a/website/server/controllers/top-level/dataexport.js
+++ b/website/server/controllers/top-level/dataexport.js
@@ -317,7 +317,7 @@ api.exportUserPrivateMessages = {
   async handler (req, res) {
     const { user } = res.locals;
 
-    const { timezoneOffset } = user.preferences;
+    const timezoneUtcOffset = user.getUtcOffset();
     const dateFormat = user.preferences.dateFormat.toUpperCase();
     const TO = res.t('to');
     const FROM = res.t('from');
@@ -329,7 +329,7 @@ api.exportUserPrivateMessages = {
     inbox.forEach((message, index) => {
       const recipientLabel = message.sent ? TO : FROM;
       const messageUser = message.user;
-      const timestamp = moment.utc(message.timestamp).zone(timezoneOffset).format(`${dateFormat} HH:mm:ss`);
+      const timestamp = moment.utc(message.timestamp).utcOffset(timezoneUtcOffset).format(`${dateFormat} HH:mm:ss`);
       const text = md.render(message.text);
       const pageIndex = `(${index + 1}/${inbox.length})`;
       messages += `
diff --git a/website/server/libs/cron.js b/website/server/libs/cron.js
index 2c9d266bc8..774309ecb5 100644
--- a/website/server/libs/cron.js
+++ b/website/server/libs/cron.js
@@ -172,7 +172,7 @@ function resetHabitCounters (user, tasksByType, now, daysMissed) {
       break;
     }
     const thatDay = moment(now)
-      .zone(user.preferences.timezoneOffset + user.preferences.dayStart * 60)
+      .utcOffset(user.getUtcOffset() - user.preferences.dayStart * 60)
       .subtract({ days: i });
     if (thatDay.day() === 1) {
       resetWeekly = true;
@@ -281,14 +281,14 @@ function awardLoginIncentives (user) {
 // Perform various beginning-of-day reset actions.
 export function cron (options = {}) {
   const {
-    user, tasksByType, analytics, now = new Date(), daysMissed, timezoneOffsetFromUserPrefs,
+    user, tasksByType, analytics, now = new Date(), daysMissed, timezoneUtcOffsetFromUserPrefs,
   } = options;
   let _progress = { down: 0, up: 0, collectedItems: 0 };
 
   // Record pre-cron values of HP and MP to show notifications later
   const beforeCronStats = _.pick(user.stats, ['hp', 'mp']);
 
-  user.preferences.timezoneOffsetAtLastCron = timezoneOffsetFromUserPrefs;
+  user.preferences.timezoneOffsetAtLastCron = -timezoneUtcOffsetFromUserPrefs;
   // User is only allowed a certain number of drops a day. This resets the count.
   if (user.items.lastDrop.count > 0) user.items.lastDrop.count = 0;
 
diff --git a/website/server/libs/preening.js b/website/server/libs/preening.js
index a6a4bb64e7..30228e2d29 100644
--- a/website/server/libs/preening.js
+++ b/website/server/libs/preening.js
@@ -2,10 +2,10 @@ import _ from 'lodash';
 import moment from 'moment';
 
 // Aggregate entries
-function _aggregate (history, aggregateBy, timezoneOffset, dayStart) {
+function _aggregate (history, aggregateBy, timezoneUtcOffset, dayStart) {
   return _.chain(history)
     .groupBy(entry => { // group entries by aggregateBy
-      const entryDate = moment(entry.date).zone(timezoneOffset);
+      const entryDate = moment(entry.date).utcOffset(timezoneUtcOffset);
       if (entryDate.hour() < dayStart) entryDate.subtract(1, 'day');
       return entryDate.format(aggregateBy);
     })
@@ -35,16 +35,16 @@ Subscribers and challenges:
 - 1 value each month for the previous 12 months
 - 1 value each year for the previous years
  */
-export function preenHistory (history, isSubscribed, timezoneOffset = 0, dayStart = 0) {
+export function preenHistory (history, isSubscribed, timezoneUtcOffset = 0, dayStart = 0) {
   // history = _.filter(history, historyEntry => Boolean(historyEntry)); // Filter missing entries
-  const now = moment().zone(timezoneOffset);
+  const now = moment().utcOffset(timezoneUtcOffset);
   // Date after which to begin compressing data
   const cutOff = now.subtract(isSubscribed ? 365 : 60, 'days').startOf('day');
 
   // Keep uncompressed entries (modifies history and returns removed items)
   const newHistory = _.remove(history, entry => {
     if (!entry) return true; // sometimes entries are `null`
-    const entryDate = moment(entry.date).zone(timezoneOffset);
+    const entryDate = moment(entry.date).utcOffset(timezoneUtcOffset);
     if (entryDate.hour() < dayStart) entryDate.subtract(1, 'day');
     return entryDate.isSame(cutOff) || entryDate.isAfter(cutOff);
   });
@@ -53,13 +53,13 @@ export function preenHistory (history, isSubscribed, timezoneOffset = 0, dayStar
   const monthsCutOff = cutOff.subtract(isSubscribed ? 12 : 10, 'months').startOf('day');
   const aggregateByMonth = _.remove(history, entry => {
     if (!entry) return true; // sometimes entries are `null`
-    const entryDate = moment(entry.date).zone(timezoneOffset);
+    const entryDate = moment(entry.date).utcOffset(timezoneUtcOffset);
     if (entryDate.hour() < dayStart) entryDate.subtract(1, 'day');
     return entryDate.isSame(monthsCutOff) || entryDate.isAfter(monthsCutOff);
   });
   // Aggregate remaining entries by month and year
-  if (aggregateByMonth.length > 0) newHistory.unshift(..._aggregate(aggregateByMonth, 'YYYYMM', timezoneOffset, dayStart));
-  if (history.length > 0) newHistory.unshift(..._aggregate(history, 'YYYY', timezoneOffset, dayStart));
+  if (aggregateByMonth.length > 0) newHistory.unshift(..._aggregate(aggregateByMonth, 'YYYYMM', timezoneUtcOffset, dayStart));
+  if (history.length > 0) newHistory.unshift(..._aggregate(history, 'YYYY', timezoneUtcOffset, dayStart));
 
   return newHistory;
 }
@@ -67,13 +67,13 @@ export function preenHistory (history, isSubscribed, timezoneOffset = 0, dayStar
 // Preen history for users and tasks.
 export function preenUserHistory (user, tasksByType) {
   const isSubscribed = user.isSubscribed();
-  const { timezoneOffset } = user.preferences;
+  const timezoneUtcOffset = user.getUtcOffset();
   const { dayStart } = user.preferences;
   const minHistoryLength = isSubscribed ? 365 : 60;
 
   function _processTask (task) {
     if (task.history && task.history.length > minHistoryLength) {
-      task.history = preenHistory(task.history, isSubscribed, timezoneOffset, dayStart);
+      task.history = preenHistory(task.history, isSubscribed, timezoneUtcOffset, dayStart);
       task.markModified('history');
     }
   }
@@ -82,12 +82,14 @@ export function preenUserHistory (user, tasksByType) {
   tasksByType.dailys.forEach(_processTask);
 
   if (user.history.exp.length > minHistoryLength) {
-    user.history.exp = preenHistory(user.history.exp, isSubscribed, timezoneOffset, dayStart);
+    user.history.exp = preenHistory(user.history.exp, isSubscribed, timezoneUtcOffset, dayStart);
     user.markModified('history.exp');
   }
 
   if (user.history.todos.length > minHistoryLength) {
-    user.history.todos = preenHistory(user.history.todos, isSubscribed, timezoneOffset, dayStart);
+    user.history.todos = preenHistory(
+      user.history.todos, isSubscribed, timezoneUtcOffset, dayStart,
+    );
     user.markModified('history.todos');
   }
 }
diff --git a/website/server/middlewares/cron.js b/website/server/middlewares/cron.js
index 365acaefd6..62e1e85a68 100644
--- a/website/server/middlewares/cron.js
+++ b/website/server/middlewares/cron.js
@@ -64,7 +64,7 @@ async function cronAsync (req, res) {
 
     user = await User.findOne({ _id: user._id }).exec();
     res.locals.user = user;
-    const { daysMissed, timezoneOffsetFromUserPrefs } = user.daysUserHasMissed(now, req);
+    const { daysMissed, timezoneUtcOffsetFromUserPrefs } = user.daysUserHasMissed(now, req);
 
     await updateLastCron(user, now);
 
@@ -94,7 +94,7 @@ async function cronAsync (req, res) {
       now,
       daysMissed,
       analytics,
-      timezoneOffsetFromUserPrefs,
+      timezoneUtcOffsetFromUserPrefs,
       headers: req.headers,
     });
 
diff --git a/website/server/models/user/methods.js b/website/server/models/user/methods.js
index 4bbe05decc..9c7d0d9a7c 100644
--- a/website/server/models/user/methods.js
+++ b/website/server/models/user/methods.js
@@ -347,35 +347,40 @@ schema.methods.cancelSubscription = async function cancelSubscription (options =
   return payments.cancelSubscription(options);
 };
 
+schema.methods.getUtcOffset = function getUtcOffset () {
+  return common.fns.getUtcOffset(this);
+};
+
 schema.methods.daysUserHasMissed = function daysUserHasMissed (now, req = {}) {
   // If the user's timezone has changed (due to travel or daylight savings),
   // cron can be triggered twice in one day, so we check for that and use
   // both timezones to work out if cron should run.
   // CDS = Custom Day Start time.
-  let timezoneOffsetFromUserPrefs = this.preferences.timezoneOffset;
-  const timezoneOffsetAtLastCron = Number.isFinite(this.preferences.timezoneOffsetAtLastCron)
-    ? this.preferences.timezoneOffsetAtLastCron
-    : timezoneOffsetFromUserPrefs;
-  let timezoneOffsetFromBrowser = typeof req.header === 'function' && Number(req.header('x-user-timezoneoffset'));
-  timezoneOffsetFromBrowser = Number.isFinite(timezoneOffsetFromBrowser)
-    ? timezoneOffsetFromBrowser
-    : timezoneOffsetFromUserPrefs;
+  let timezoneUtcOffsetFromUserPrefs = this.getUtcOffset();
+  const timezoneUtcOffsetAtLastCron = Number.isFinite(this.preferences.timezoneOffsetAtLastCron)
+    ? -this.preferences.timezoneOffsetAtLastCron
+    : timezoneUtcOffsetFromUserPrefs;
+
+  let timezoneUtcOffsetFromBrowser = typeof req.header === 'function' && -Number(req.header('x-user-timezoneoffset'));
+  timezoneUtcOffsetFromBrowser = Number.isFinite(timezoneUtcOffsetFromBrowser)
+    ? timezoneUtcOffsetFromBrowser
+    : timezoneUtcOffsetFromUserPrefs;
   // NB: All timezone offsets can be 0, so can't use `... || ...` to apply non-zero defaults
 
-  if (timezoneOffsetFromBrowser !== timezoneOffsetFromUserPrefs) {
+  if (timezoneUtcOffsetFromBrowser !== timezoneUtcOffsetFromUserPrefs) {
     // The user's browser has just told Habitica that the user's timezone has
     // changed so store and use the new zone.
-    this.preferences.timezoneOffset = timezoneOffsetFromBrowser;
-    timezoneOffsetFromUserPrefs = timezoneOffsetFromBrowser;
+    this.preferences.timezoneOffset = -timezoneUtcOffsetFromBrowser;
+    timezoneUtcOffsetFromUserPrefs = timezoneUtcOffsetFromBrowser;
   }
 
   // How many days have we missed using the user's current timezone:
   let daysMissed = daysSince(this.lastCron, defaults({ now }, this.preferences));
 
-  if (timezoneOffsetAtLastCron !== timezoneOffsetFromUserPrefs) {
+  if (timezoneUtcOffsetAtLastCron !== timezoneUtcOffsetFromUserPrefs) {
     // Give the user extra time based on the difference in timezones
-    if (timezoneOffsetAtLastCron < timezoneOffsetFromUserPrefs) {
-      const differenceBetweenTimezonesInMinutes = timezoneOffsetFromUserPrefs - timezoneOffsetAtLastCron; // eslint-disable-line max-len
+    if (timezoneUtcOffsetAtLastCron > timezoneUtcOffsetFromUserPrefs) {
+      const differenceBetweenTimezonesInMinutes = timezoneUtcOffsetAtLastCron - timezoneUtcOffsetFromUserPrefs; // eslint-disable-line max-len
       now = moment(now).subtract(differenceBetweenTimezonesInMinutes, 'minutes'); // eslint-disable-line no-param-reassign, max-len
     }
 
@@ -384,13 +389,13 @@ schema.methods.daysUserHasMissed = function daysUserHasMissed (now, req = {}) {
     const daysMissedNewZone = daysMissed;
     const daysMissedOldZone = daysSince(this.lastCron, defaults({
       now,
-      timezoneOffsetOverride: timezoneOffsetAtLastCron,
+      timezoneUtcOffsetOverride: timezoneUtcOffsetAtLastCron,
     }, this.preferences));
 
-    if (timezoneOffsetAtLastCron < timezoneOffsetFromUserPrefs) {
+    if (timezoneUtcOffsetAtLastCron > timezoneUtcOffsetFromUserPrefs) {
       // The timezone change was in the unsafe direction.
-      // E.g., timezone changes from UTC+1 (offset -60) to UTC+0 (offset 0).
-      //    or timezone changes from UTC-4 (offset 240) to UTC-5 (offset 300).
+      // E.g., timezone changes from UTC+1 (utcOffset 60) to UTC+0 (offset 0).
+      //    or timezone changes from UTC-4 (utcOffset -240) to UTC-5 (utcOffset -300).
       // Local time changed from, for example, 03:00 to 02:00.
 
       if (daysMissedOldZone > 0 && daysMissedNewZone > 0) {
@@ -419,20 +424,21 @@ schema.methods.daysUserHasMissed = function daysUserHasMissed (now, req = {}) {
         // timezone interprets as being in today.
 
         daysMissed = 0; // prevent cron running now
-        const timezoneOffsetDiff = timezoneOffsetAtLastCron - timezoneOffsetFromUserPrefs;
-        // e.g., for dangerous zone change: 240 - 300 = -60 or  -660 - -600 = -60
+        const timezoneOffsetDiff = timezoneUtcOffsetFromUserPrefs - timezoneUtcOffsetAtLastCron;
+        // e.g., for dangerous zone change: -300 - -240 = -60 or 600 - 660= -60
 
         this.lastCron = moment(this.lastCron).subtract(timezoneOffsetDiff, 'minutes');
         // NB: We don't change this.auth.timestamps.loggedin so that will still record
         // the time that the previous cron actually ran.
         // From now on we can ignore the old timezone:
-        this.preferences.timezoneOffsetAtLastCron = timezoneOffsetFromUserPrefs;
+        // This is still timezoneOffset for backwards compatibility reasons.
+        this.preferences.timezoneOffsetAtLastCron = -timezoneUtcOffsetAtLastCron;
       } else {
         // Both old and new timezones indicate that cron should
         // NOT run.
         daysMissed = 0; // prevent cron running now
       }
-    } else if (timezoneOffsetAtLastCron > timezoneOffsetFromUserPrefs) {
+    } else if (timezoneUtcOffsetAtLastCron < timezoneUtcOffsetFromUserPrefs) {
       daysMissed = daysMissedNewZone;
       // TODO: Either confirm that there is nothing that could possibly go wrong
       // here and remove the need for this else branch, or fix stuff.
@@ -445,7 +451,7 @@ schema.methods.daysUserHasMissed = function daysUserHasMissed (now, req = {}) {
     }
   }
 
-  return { daysMissed, timezoneOffsetFromUserPrefs };
+  return { daysMissed, timezoneUtcOffsetFromUserPrefs };
 };
 
 async function getUserGroupData (user) {