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# system

The time zone currently used by the system.

```
class var system: TimeZone { get }
```

## Discussion

If the current system time zone cannot be determined, the GMT time zone is used instead.

If you access the [`system`](/documentation/Foundation/NSTimeZone/system) class property, its value is cached by the app and doesn’t update if the user subsequently changes the system time zone. In order for the [`system`](/documentation/Foundation/NSTimeZone/system) property to reflect the new time zone, you must first call the [`resetSystemTimeZone()`](/documentation/Foundation/NSTimeZone/resetSystemTimeZone()) method to clear the cached value. Then, the next time you access the [`system`](/documentation/Foundation/NSTimeZone/system) property, it returns the current system time zone, and caches that value.

If you access the [`system`](/documentation/Foundation/NSTimeZone/system) class property, assign its value to a variable, and clear the cached value for the property by calling the [`resetSystemTimeZone()`](/documentation/Foundation/NSTimeZone/resetSystemTimeZone()) method, the object stored in the variable doesn’t update to reflect the new system time zone. Contrast this behavior with that of the [`local`](/documentation/Foundation/NSTimeZone/local) class property, which returns a proxy object that always reflects the current system time zone.

---

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