United States Time Zones
Daylight time begins
in the United States on the second Sunday in March and ends on the first Sunday in
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.
Not all places in
the U.S. observe daylight time (such as Arizona, Hawaii, American Samoa, Guam, Puerto Rico, and the Virgin Islands).
In 2011, daylight time begins on March 13 and ends on November 6.
In 2012, daylight time begins on March 11 and ends on November 4.
In 2013, daylight time begins on March 10 and ends on November 3.
Many other countries
observe some form of "summer time", but they do not necessarily change their
clocks on the same dates as the U.S.