To Change the Time Zone

The login server sets the TZ environment variable when it runs the Xsetup, Xstartup, Xsession, Xfailsafe, and Xreset scripts. The default value is derived from the system so usually you will not need to change this behavior. To provide an alternate time zone to these scripts, set the Dtlogin.timeZone resource in Xconfig. For example:

Dtlogin.timeZone: CST6CDT