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. The act explicitly preempted all previously enacted state laws related to the beginning and ending of DST effective in 1966. Any state that wanted to be exempt from DST could do so by passing a state law, provided that it exempted the entire state, and Alaska, Arizona, Hawaii, Indiana, and Michigan chose to do so. However, Alaska, Indiana, and Michigan subsequently chose to observe DST. The law was amended in 1972 to permit states that straddle a time zone boundary to exempt the entire area of the state lying in one time zone. Indiana chose to exempt the portion of the state lying in the Eastern Time Zone; however, that exemption was eliminated in 2006 and the entire state of Indiana now observes DST, leaving Arizona (with the exception of the Navajo Nation) and Hawaii as the only two states not to observe DST. On July 8, 1986, President Ronald Reagan signed the Federal Fire Prevention and Control Act of 1986 into law that contained a daylight saving rider authored by Senator Slade Gorton (R - WA). The starting date of DST was amended to the first Sunday in April effective in 1987. DST continued to end on the last Sunday in October. While the states retain the capability to exempt themselves from DST, they are forbidden by the 1966 federal law (15 USC 260a (b)) from increasing a state 's time spent on DST, unless the United States Congress does this for the entire nation.
when did daylight saving time begin in the united states
1967