During DST, clocks are turned forward an hour, effectively moving an hour of daylight from the morning to the evening.

http://webexhibits.org/daylightsaving/b.html

Beginning in 2007, most of the United States begins Daylight Saving Time at 2:00 a.m. on the second Sunday in March and reverts to standard time on the first Sunday in November. In the U.S., each time zone switches at a different time.