You can use the time zones below for most US based time zones so that the time automatically changes when daylight savings time starts and ends.
Central Standard Time use CST6CDT
Eastern Standard Time use EST5EDT
Mountain Standard Time use MST7MDT
Pacific Standard Time use PST8PDT
For some regions such as Phoenix Arizona which do not use Daylight Savings time, you can choose "America/Phoenix" or choose the City specific time zone which matches up with your desired region.