diff --git a/server/src/utils/date.spec.ts b/server/src/utils/date.spec.ts
index 476b5cb526..36fdef1adc 100644
--- a/server/src/utils/date.spec.ts
+++ b/server/src/utils/date.spec.ts
@@ -1,5 +1,6 @@
+import { Settings } from 'luxon';
 import { asDateString, asDateTimeString } from 'src/utils/date';
-import { describe, expect, it } from 'vitest';
+import { afterEach, describe, expect, it } from 'vitest';
 
 describe('asDateString', () => {
   it('should return null for null input', () => {
@@ -10,11 +11,20 @@ describe('asDateString', () => {
     expect(asDateString('2000-01-15')).toBe('2000-01-15');
   });
 
-  it('should return the local calendar date, not the UTC date', () => {
-    const date = new Date(2000, 0, 15); // 15 Jan 2000, local midnight
+  afterEach(() => {
+    Settings.defaultZone = 'system';
+  });
+
+  it('should return the UTC calendar date', () => {
+    const date = new Date('2000-01-15'); // parsed as UTC midnight, like a database `date` column
     expect(asDateString(date)).toBe('2000-01-15');
   });
 
+  it('should not shift the date when the server runs in a timezone behind UTC', () => {
+    Settings.defaultZone = 'America/Chicago';
+    expect(asDateString(new Date('1994-09-01'))).toBe('1994-09-01');
+  });
+
   it('should correctly pad years with a leading 0', () => {
     expect(asDateString(new Date('280-12-12'))).toBe('0280-12-12');
   });
diff --git a/server/src/validation.ts b/server/src/validation.ts
index f8de2a68ff..0ce78eccd0 100644
--- a/server/src/validation.ts
+++ b/server/src/validation.ts
@@ -161,7 +161,7 @@ export const isoDateToDate = z
     z.date(),
     {
       decode: (isoString) => new Date(isoString),
-      encode: (date) => DateTime.fromJSDate(date).toFormat('yyyy-MM-dd'),
+      encode: (date) => DateTime.fromJSDate(date, { zone: 'utc' }).toFormat('yyyy-MM-dd'),
     },
   )
   .meta({ example: '2024-01-01' });