Use Date & Time System Preferences to change the date and time on your Mac. You can have the date and time set automatically using a network time server, or set your computer’s date and time manually. Be sure your time is correct so time stamps on emails, messages, and files are correct.
To change these preferences, choose Apple menu > System Preferences, then click Date & Time.
Set the time automatically: Select “Set date and time automatically,” click the pop-up menu, then choose the server that’s closest to you, or type the address of your network time server.
If your Mac isn’t connected to the Internet, it connects when you choose this option.
Set the time manually: Deselect “Set date and time automatically.” Click today’s date on the calendar, drag the clock’s hands to show the correct time (or enter the time), then click Save.
You can also use the up and down arrows next to the date or time field, or type over the current date or time.
Set the time zone automatically: Select “Set time zone automatically using current location.”
Set the time zone manually: Deselect “Set time zone automatically using current location,” click a location on the map, click the Closest City pop-up menu, then choose the city closest to your location.
Show date and time in menu bar: Select the checkbox to see the date and time in the top-right corner of the menu bar. In “Time options” and “Date options,” set how you want the date and time to appear.
Announce the time: Select the checkbox to hear the time announced, then choose when you want it announced. If you want, you can customize the voice.