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| | Daylight saving time - Wikipedia, the free encyclopedia |
 | | Daylight saving time (DST), also known as summer time and sometimes referred to as daylight savings time, is a widely used system of adjusting the official local time forward, usually by one hour from its official standard time, for the summer months. |
 | | On March 19, 1918, the U.S. Congress established several time zones, which had been in use by railroads and most cities since 1883 and made DST official, effective March 31, for the remainder of World War I. It was observed for seven months in 1918 and 1919. |
 | | The U.S. federal Uniform Time Act became law on April 13, 1966 and it mandated that DST begin nationwide on the last Sunday in April and end on the last Sunday in October, effective in 1967. |
| en.wikipedia.org /wiki/Daylight_saving_time (6735 words) |
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