EST (Eastern Standard Time): GMT-5
CST (Central Standard Time): GMT-6
MST (Mountain Standard Time): GMT-7
PST (Pacific Standard Time): GMT-8
In addition there are two further zones for:
Alaskan Time: GMT-9
Hawaiian Time: GMT-10
GMT: Greenwich Mean Time
MEZ: Middle European Timezone: MEZ is GMT + 1 hr
Daylight Saving Time (DST) in the USA
DST 2013: Sunday, March 10 until Sunday, November 3, 2013
DST (=turn clock 1 hr ahead) will begin at 2 a.m. on the second Sunday in March
and Standard Time (=turn clock 1 hr back) will begin at 2 a.m. on the first Sunday in November.
On August 8, 2005, President Bush signed the Energy Policy Act of 2005, which included changes in Daylight Saving Time, effective March 1, 2007.
Source: Physics Laboratory, U.S. National Institute of Standards & Technology