Germany adopted DST in April 1916, with Great Britain following May 1916.
Daylight Saving Time (DST) was not formally adopted in the U.S. until 1918, as part of the establishment of standard time zones (Ben Franklin is widely credited with the notion, expressed in his 1784 ” Essay on Daylight Saving .” Even then, DST was only observed for seven months in 1918 and 1919, but after World War I ended, the law proved so unpopular (mostly because people rose earlier and went to bed earlier than today), it was repealed in 1919 with a Congressional override of President Woodrow Wilson’s veto.
The Uniform Time Act, passed in 1966, established a system of uniform (within each time zone) daylight savings time throughout the U.S. and its possessions, except where legislatures voted to keep the entire state on standard time (these days that is Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands, and in most of Arizona – the exception being the Navajo Indian Reservation there, which does recognize DST).
More information is available at http://www.plansponsor.com/Cooling_Off_Periods_.aspx
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 Congress in the Energy Policy Act of 2005, Pub. L. no. 109-58, 119 Stat 594 (2005).
More information is available at http://aa.usno.navy.mil/faq/docs/daylight_time.php