diff --git a/CHANGELOG.md b/CHANGELOG.md
index 72786a49c..863376cae 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added support for filtering in the public access for portfolio sharing (experimental)
 - Set up the language localization for Japanese (`ja`)
 
+### Fixed
+
+- Fixed the time zone handling in the `api` test suite for deterministic execution in `UTC`
+
 ## 3.17.0 - 2026-06-26
 
 ### Added
diff --git a/apps/api/jest.config.ts b/apps/api/jest.config.ts
index b87f91a79..805710396 100644
--- a/apps/api/jest.config.ts
+++ b/apps/api/jest.config.ts
@@ -1,4 +1,8 @@
 /* eslint-disable */
+
+// Run tests in UTC for deterministic date-based calculations
+process.env.TZ = 'UTC';
+
 export default {
   displayName: 'api',