diff --git a/src/common/translations/localize.ts b/src/common/translations/localize.ts
index a094d48b3e..6ff6e24b90 100644
--- a/src/common/translations/localize.ts
+++ b/src/common/translations/localize.ts
@@ -32,6 +32,7 @@ if (__BUILD__ === "latest") {
   }
   if (shouldPolyfillDateTime()) {
     polyfills.push(import("@formatjs/intl-datetimeformat/polyfill"));
+    polyfills.push(import("@formatjs/intl-datetimeformat/add-all-tz"));
   }
 }
 
diff --git a/src/state/connection-mixin.ts b/src/state/connection-mixin.ts
index 5c5f0b1468..5858ac67ef 100644
--- a/src/state/connection-mixin.ts
+++ b/src/state/connection-mixin.ts
@@ -24,6 +24,7 @@ import { getState } from "../util/ha-pref-storage";
 import hassCallApi from "../util/hass-call-api";
 import { getLocalLanguage } from "../util/common-translation";
 import { HassBaseEl } from "./hass-base-mixin";
+import { polyfillsLoaded } from "../common/translations/localize";
 
 export const connectionMixin = <T extends Constructor<HassBaseEl>>(
   superClass: T
@@ -180,12 +181,18 @@ export const connectionMixin = <T extends Constructor<HassBaseEl>>(
 
       subscribeEntities(conn, (states) => this._updateHass({ states }));
       subscribeConfig(conn, (config) => {
-        if (
-          this.hass?.config?.time_zone !== config.time_zone &&
-          "__setDefaultTimeZone" in Intl.DateTimeFormat
-        ) {
-          // @ts-ignore
-          Intl.DateTimeFormat.__setDefaultTimeZone(config.time_zone);
+        if (this.hass?.config?.time_zone !== config.time_zone) {
+          if (__BUILD__ === "latest" && polyfillsLoaded) {
+            polyfillsLoaded.then(() => {
+              if ("__setDefaultTimeZone" in Intl.DateTimeFormat) {
+                // @ts-ignore
+                Intl.DateTimeFormat.__setDefaultTimeZone(config.time_zone);
+              }
+            });
+          } else if ("__setDefaultTimeZone" in Intl.DateTimeFormat) {
+            // @ts-ignore
+            Intl.DateTimeFormat.__setDefaultTimeZone(config.time_zone);
+          }
         }
         this._updateHass({ config });
       });