diff --git a/src/lib/yup.ts b/src/lib/yup.ts
index 2407f7ad..5bd0aa18 100644
--- a/src/lib/yup.ts
+++ b/src/lib/yup.ts
@@ -2,11 +2,14 @@ import moment from 'moment';
 import * as yup from 'yup';
 import { UNIT_TYPES } from './constants';
 
-export const TimezoneTest = yup.string().test(
-  'timezone',
-  () => `Invalid timezone`,
-  value => moment.tz.zone(value) !== null,
-);
+export const TimezoneTest = yup
+  .string()
+  .default('UTC')
+  .test(
+    'timezone',
+    () => `Invalid timezone`,
+    value => moment.tz.zone(value) !== null,
+  );
 
 export const UnitTypeTest = yup.string().test(
   'unit',