'Fall back' Sunday: Where and when does daylight saving time end?

The end of daylight saving time is quickly approaching for much of the United States. 

Standard time begins at 2 a.m. local time on Sunday. Millions of Americans will set their clocks back an hour before bed on Saturday, gaining an hour of sleep

But the switch isn't observed everywhere, even in the U.S.

Hawaii, most of Arizona, American Samoa, Guam, Puerto Rico and the U.S. Virgin Islands forgo the time change. 

Some states want to end the tradition of "falling back" and "springing forward" entirely, although there is no consensus behind which should be used all year.

This change would require that federal law be altered, though 19 states have enacted legislation or passed resolutions to provide for year-round daylight saving time, according to NPR.

Twenty-nine states introduced legislation to abolish resetting the clocks between 2015 and 2019, according to the U.S. Department of Transportation

The department explained that the time zones were introduced by major railroad companies in 1883 to resolve confusion and avoid train crashes caused by different local times.

As the U.S. entered World War I in 1918, the government delegated time zone supervision to the railroad regulating Interstate Commerce Commission (ICC), which oversaw the concept of daylight saving time. 

DST was initially introduced by Germany during the war to conserve fuel and power by extending daylight hours, and the U.S. followed suit.

After the war, DST was nationally abolished and allowed to continue on a state-by-state basis – which led to confusion and collisions caused by different local times. 

After the Transportation Department's founding in 1966, DST was implemented uniformly across the nation through the Uniform Time Act, with dates for the twice-yearly transitions set by law.

Every state must continue to observe DST between March and November unless exempted by state law. 

After a previous shift in 1986, the time period for DST was extended by four weeks through the 2005 Energy Policy Act. The rule – implemented in 2007 – changed the start of daylight saving to the second Sunday in March and its end to the first Sunday in November.

Across the world, more than 70 countries observe DST. 

Daylight saving time returns at 2 a.m. local time on Sunday, March 13, 2022.