From MEPIS Documentation Wiki
Setting The Time Zone
Using Control Center
From the menu select Control Center, then System Administration, then Date and Time.
You must click on the Administrator Mode button and enter the root password to change the time zone setting.
You can now select a city that is in your time zone.
To move quickly through the list click on any entry and then press the first letter of the city you want to choose and you will be moved there.
By default the list is sorted alphabetically by city names. To sort by another heading click on that heading.
From The Console (terminal)
Open a terminal window and enter the command date. This will display the current date and the time zone abbreviation.
You have to enter the root password to change the time zone. After entering the root password you enter the command:
You will now be prompted for the information needed to set your time zone.
Select the geographic area from the list using the cursor keys and then tab to OK and press the enter key.
Select a city in your time zone from the list using the cursor keys and then tab to OK and press the enter key.
When you are done you should see a screen like the one below.