Set 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.
On your Mac, choose Apple menu > System Settings, click General in the sidebar, then click Date & Time on the right. (You may need to scroll down.)
Set the date and time automatically or manually.
Automatically: Turn on “Set time and date automatically,” click Set, then enter a network time server for your region.
Manually: Turn off “Set time and date automatically,” click Set, enter the date and time, then click Set.
Set the time zone automatically or manually.
Automatically: Turn on “Set time zone automatically using your current location.”
Manually: Turn off “Set time zone automatically using your current location,” click Set, enter a city in the text field, select the full city name from the list, then click OK.
To choose the formats used to show dates and times in other languages on your Mac, see Change how dates, times, and more display.
Tip: Click the date and time in the menu bar to open Notification Center. See Use Notification Center.