Summary
Daylight Saving Time (DST) in the United States starts in March and ends in November. Not all U.S. regions observe DST. The practice aims to make better use of daylight during warmer months, although its energy-saving benefits are debated.
Key Facts
- Daylight Saving Time starts on the second Sunday in March and ends on the first Sunday in November.
- When DST starts, clocks move forward an hour at 2 a.m., meaning one less hour in the day.
- When DST ends, clocks move back an hour at 2 a.m., adding an extra hour to the day.
- DST was first introduced in the U.S. in 1918.
- Hawaii, American territories, and most of Arizona do not observe DST.
- The Uniform Time Act of 1966 standardized DST dates, but states can opt out.
- In 2007, DST was extended by about a month for energy-saving reasons.
- DST currently covers about 65% of the year.
