Date & Time (System Preferences)

The Date & Time pane of the System Preferences in macOS allows a user to customize the built-in clock and calendar settings of their Mac. It is seldom necessary to set the time manually as Macs with Internet access can normally set time automatically by checking a network.

History
With the release of Mac OS X, the Date & Time preference pane superseded the Date & Time control panel from classic Mac OS. The functionality has changed little since then.

Interactions with other software
The Language & Region preference pane includes a 24-Hour Time button that can override the setting in the Clock tab of the Date & Time preference pane. The Calendar utility included with macOS will use the setting from the Time Zone tab of the Date & Time preference pane by default. Switching the time zone from within Calendar will allow a user to see the time for an event scheduled in another time zone without changing the overall setting for the computer.