Daylight saving time was instituted in the United States as an energy-saving measure to allow people to take maximum advantage of available daylight. Although its effects in that regard remain questionable, the practice has been a boon for summertime retail business, increasing the length of the shopping day for consumers and thereby allowing stores to increase their sales volume.

Daylight saving time has often been traced to a proposal written by Benjamin Franklin in 1784. However, he was actually satirizing the Parisian lifestyle, urging the French to rise earlier in the morning. The first serious modern daylight saving proposal was put forth in 1907 by British house builder William Willett, who sought to encourage greater outdoor activity during the summer months. In spite of considerable lobbying, he was unable to convince the British government to adopt his plan.Daylight saving time

Only the fuel shortages brought about by World War I convinced several of the belligerent nations to put daylight saving time into effect. However, it was so unpopular that all governments dropped it after the armistice. The United States reinstated mandatory daylight saving time as an energy-conservation measure during World War II, but after the war ended, the federal government left the decision to retain daylight saving time up to the individual states. In 1966, Congress passed the Uniform Time Act of 1966Uniform Time Act, which required all states observing daylight saving time to begin and end it on the same day each year. During the 1973 Arab oil embargo, the federal government temporarily mandated an early beginning to daylight saving time for 1974 and 1975.

Opponents have criticized daylight saving time as saving nothing, since it merely moves the observed hours forward rather than adding a real hour. In addition, there are serious questions about whether it realizes any energy savings in a society in which lighting is a relatively minor consumer of power compared with computers and other technology. By contrast, retail businesses tend to favor daylight saving, because it often results in consumers shopping later in the afternoon and evening, producing more revenue for stores.

Several U.S. states do not observe daylight saving time. For decades it was resisted by Indiana, which straddles the eastern and central time zones, but the state has adopted a unified time except for a few counties adjacent to Chicago or Louisville. In 2005, a law was passed by the Indiana General Assembly putting all of Indiana on daylight saving time beginning in 2006. Arizona also does not observe daylight saving time, except in several of the nominally sovereign Native American reservations.

The Energy Policy Act of 2005Energy Policy Act of 2005 lengthened the duration of daylight saving time in the United States beginning in 2007. From 1966 to 2006, daylight saving time began in the United States on the first Sunday in April and ended on the last Sunday in October. After 2006, it began on the second Sunday in March and ended on the first Sunday in November. The law, designed to increase energy savings, was motivated by concern over the nation’s growing energy problems and the possibility of a looming crisis.

• Barnett, Jo Ellen. Time’s Pendulum: From Sundials to Atomic Clocks, the Fascinating History of Timekeeping and How Our Discoveries Changed the World. San Diego, Calif.: Harcourt Brace, 1999.
• Dolan, Graham. The Greenwich Guide to Measuring Time. Chicago: Heinemann Library, 2001.

Arab oil embargo of 1973

U.S. Department of Energy

Energy crisis of 1979

Benjamin Franklin

Public utilities

Time zones