diff --git a/packages/clock/src/ClockConfig.php b/packages/clock/src/ClockConfig.php
index a9c292d..8d0a354 100644
--- a/packages/clock/src/ClockConfig.php
+++ b/packages/clock/src/ClockConfig.php
@@ -5,34 +5,40 @@
 namespace A50\Clock;
 
 use DateTimeZone;
+use Exception;
 use Webmozart\Assert\Assert;
 
 final class ClockConfig
 {
-    private string $timezone;
+    private DateTimeZone $timezone;
 
+    /**
+     * @throws Exception
+     */
     private function __construct(string $timezone)
     {
         Assert::inArray($timezone, DateTimeZone::listIdentifiers(DateTimeZone::ALL));
-        $this->timezone = $timezone;
+        $this->timezone = new DateTimeZone($timezone);
     }
 
+    /**
+     * @throws Exception
+     */
     public static function withDefaults(
         string $timezone = 'UTC',
     ): self {
         return new self($timezone);
     }
 
+    /**
+     * @throws Exception
+     */
     public function withTimezoneChanged(string $timezone): self
     {
-        Assert::inArray($timezone, DateTimeZone::listIdentifiers(DateTimeZone::ALL));
-        $new = clone $this;
-        $new->timezone = $timezone;
-
-        return $new;
+        return new self($timezone);
     }
 
-    public function timezone(): string
+    public function timezone(): DateTimeZone
     {
         return $this->timezone;
     }
diff --git a/packages/clock/src/ClockProvider.php b/packages/clock/src/ClockProvider.php
index da7152f..6e2dfba 100644
--- a/packages/clock/src/ClockProvider.php
+++ b/packages/clock/src/ClockProvider.php
@@ -19,7 +19,7 @@ public static function getDefinitions(): array
                 /** @var ClockConfig $config */
                 $config = $container->get(ClockConfig::class);
 
-                return new TimeZoneAwareClock(new DateTimeZone($config->timezone()));
+                return new TimeZoneAwareClock($config->timezone());
             },
         ];
     }