Daylight Saving

Daylight Saving, system of setting clocks ahead so that both sunrise and sunset occur at a later hour, producing an additional period of daylight in the evening. In the North Temperate Zone clocks are usually set ahead one hour in the spring and set back to standard time in the fall. The correct adjustment is easily remembered via the mantra “spring forward, fall back.”

Beginning in 2007 daylight-saving time in most of the United States and Canada has started at 2 am on the second Sunday of March and has ended at 2 am on the first Sunday of November. Intended to promote energy conservation by starting daylight saving three weeks earlier and ending it one week later, the change was part of the Energy Policy Act of 2005, passed by the U.S. Congress. Daylight saving is not observed in Hawaii, Arizona, Puerto Rico, Virgin Islands, Guam, and American Samoa. In Canada, daylight saving is not observed in most of Saskatchewan and in some towns and areas elsewhere. The province of Newfoundland and Labrador observes daylight saving but starts and ends at one minute after midnight on the spring and fall dates instead of at 2 am.

The idea of daylight saving was mentioned in a whimsical essay in 1784 by Benjamin Franklin; it was first advocated seriously by a British builder, William Willett, in the pamphlet Waste of Daylight (1907). Daylight saving has been used in the United States and in many European countries since World War I (1914-1918), when the system was adopted in order to conserve fuel needed to produce electric power. Some localities reverted to standard time after the war, but others retained daylight saving. During World War II (1939-1945) the U.S. Congress passed a law putting the entire country on “war time,” which set clocks one hour ahead of standard time for the duration of the war. War time was also followed in Britain, where clocks were put ahead still another hour during the summer.

In the United States during peacetime, daylight saving was a subject of controversy. Farmers, who usually work schedules determined by Sun time and are therefore inconvenienced when they must conduct business on a different time basis, registered strong opposition. Railroad, bus, and plane scheduling was hampered by time inconsistencies among various cities and states. The Uniform Time Act, enacted by the U.S. Congress in 1966, established a system of uniform (within each time zone) daylight-saving time throughout the United States and its possessions, exempting only those states in which the state legislature voted to keep the entire state on standard time.