Daylight Saving Time

[Dave Monroe]

Starting in 2007, daylight time begins in the United States on the
second Sunday in March and ends on the first Sunday in November. On
the second Sunday in March, clocks are set ahead one hour at 2:00
a.m.local standard time, which becomes 3:00 a.m. local daylight time.
On the first Sunday in November, clocks are set back one hour at 2:00
a.m. local daylight time, which becomes 1:00 a.m. local standard time.
These dates were established by the Energy Policy Act of 2005, Pub. L.
no. 109-58, 119 Stat 594 (2005).

Not all places in the U.S. observe daylight  time. In particular,
Hawaii and most of Arizona do not use it. Indiana adopted its use
beginning in 2006.

    * In 2008, daylight time begins on March 9 and ends on November 2.

http://aa.usno.navy.mil/faq/docs/daylight_time.php

And see as well, e.g., ...

http://en.wikipedia.org/wiki/Daylight_saving_time
http://webexhibits.org/daylightsaving/index.html
http://www.timeanddate.com/time/aboutdst.html