If your clocks display wrong times, your system time zone may be incorrectly set.
Open System Preferences, and then click Date & Time.
Click the Time Zone tab, click your part of the world on the map, and choose your closest city from the drop-down menu.
If you don't use a network time server to automatically set the date and time, click the Date & Time tab and adjust your computer's clock.
If your computer's time zone and clock are both correct but some of your clocks display wrong times, you should check each of them and, if it is showing an alternate text, verify that the associated city or time zone is correct.
Choose Pane > Clocks.
Double-click the clock in the list or select it and choose Edit Clock from the Action pop-up menu (looks like a gear) at the bottom of the list.
If the "Alternate text" field isn't empty, make sure that the city or time zone selected in the list is correct.
Show an alternate text