diff --git a/src/app/core/store/core/configuration/configuration.selectors.spec.ts b/src/app/core/store/core/configuration/configuration.selectors.spec.ts
index 1a1d554952..0de4d12cbd 100644
--- a/src/app/core/store/core/configuration/configuration.selectors.spec.ts
+++ b/src/app/core/store/core/configuration/configuration.selectors.spec.ts
@@ -19,6 +19,15 @@ import {
   getRestEndpoint,
 } from './configuration.selectors';
 
+// mock `isDevMode` to return `false`
+jest.mock('@angular/core', () => {
+  const originalModule = jest.requireActual('@angular/core');
+  return {
+    ...originalModule,
+    isDevMode: jest.fn(() => false),
+  };
+});
+
 describe('Configuration Selectors', () => {
   let store$: StoreWithSnapshots;
 
diff --git a/src/app/core/store/core/configuration/configuration.selectors.ts b/src/app/core/store/core/configuration/configuration.selectors.ts
index 3da4bb082f..6a1c85aad6 100644
--- a/src/app/core/store/core/configuration/configuration.selectors.ts
+++ b/src/app/core/store/core/configuration/configuration.selectors.ts
@@ -1,3 +1,4 @@
+import { isDevMode } from '@angular/core';
 import { createSelector, createSelectorFactory, resultMemoize } from '@ngrx/store';
 import { isEqual } from 'lodash-es';
 
@@ -59,10 +60,12 @@ export const getCurrentLocale = createSelector(
   internalDefaultLocale,
   getServerConfigParameter<string>('general.defaultLocale'),
   (available, requested, defaultLocale, configuredDefault) =>
-    available?.find(l => l === requested) ??
-    available?.find(l => l === configuredDefault) ??
-    available?.find(l => l === defaultLocale) ??
-    available?.[0]
+    isDevMode() && defaultLocale
+      ? defaultLocale
+      : available?.find(l => l === requested) ??
+        available?.find(l => l === configuredDefault) ??
+        available?.find(l => l === defaultLocale) ??
+        available?.[0]
 );
 
 export const getAvailableCurrencies = createSelector(
diff --git a/src/environments/environment.model.ts b/src/environments/environment.model.ts
index 6381ae8bf0..f1c69c381b 100644
--- a/src/environments/environment.model.ts
+++ b/src/environments/environment.model.ts
@@ -85,7 +85,7 @@ export interface Environment {
   // default device type used for initial page responses
   defaultDeviceType: DeviceType;
 
-  // default locale that is used as fallback if no default locale from the ICM REST call is available
+  // default locale that is used as fallback if no default locale from the ICM REST call is available (should only be set for local development)
   defaultLocale?: string;
 
   // configuration filtering available locales and their active currencies
@@ -146,7 +146,6 @@ export const ENVIRONMENT_DEFAULTS: Omit<Environment, 'icmChannel'> = {
   },
   defaultProductListingViewType: 'grid',
   defaultDeviceType: 'mobile',
-  defaultLocale: 'en_US',
   multiSiteLocaleMap: {
     en_US: '/en',
     de_DE: '/de',