[20070307]RS22284_夏时制时间.pdf

Order Code RS22284Updated March 7, 2007Daylight Saving TimeMark GurevitzInformation Research SpecialistKnowledge Services GroupSummaryDaylight Saving Time (DST) is currently observed in the United States from 2:00a.m. on the second Sunday in March until 2:00 a.m. on the first Sunday in November.The following states and territories do not observe DST: Arizona, Hawaii, AmericanSamoa, Puerto Rico, and the Virgin Islands. This report will be updated as needed.Historical BackgroundDaylight Saving Time (DST) is not a new concept. In 1784, when BenjaminFranklin was Minister to France, an idea occurred to him: in that part of the year when thesun rises while most people are still asleep, clocks could be reset to allow an extra hourof daylight during waking hours. He calculated that French shopkeepers could save onemillion francs per year on candles. In 1907, William Willett, a British builder, Memberof Parliament, and fellow of the Royal Astronomical Society, proposed the adoption ofadvanced time. The bill he introduced was reported favorably, asserting that DST wouldmove hours of work and recreation more closely to daylight hours, reducing expenditureson artificial light. There was much o