It’s time to step back again.
The clock will strike 1 a.m. twice on Sunday, when daylight saving time comes to an end.
Here’s what you need to know about daylight saving time and why the United States changes its clocks twice a year.
When does daylight saving time end?
Daylight saving time began on March 9 and ends on Sunday.
Unlike in the spring, when we lose an hour and the clocks completely skip the 2 o’clock time, we will gain an extra hour on Sunday, with the clocks jumping from 1:59 a.m. to 1 a.m.
The sun will also begin to set earlier in the United States as we head into late fall and winter.
How long is the standard time?
Standard time in the United States will remain, as will earlier sunsets and darker nights, until spring arrives and daylight saving time begins again.
That means daylight saving time will start again next year on March 8 and end on November 1.
Why do we observe daylight saving time?
The practice, established by the Standard Time Act in 1918, according to the Astronomical Applications Department of the United States Naval Observatory, is an effort to extend the hours of daylight we have in the summer by delaying sunset by an hour.
Daylight saving time, a controversial idea after its passage, was quickly repealed in 1919, becoming a local issue. It was reenacted during the early days of World War II and observed from 1942 to 1945, according to the department.
After the war, implementation of daylight saving time varied from state to state until the Uniform Time Act was passed in 1966, standardizing daylight saving dates but allowing local exemptions if states or localities did not want to participate.
According to the Department of Astronomical Applications, the standardized start and end dates have changed over the years, but since 2007, daylight saving time begins on the second Sunday in March and ends on the first Sunday in November.
What states do they not observe?
Hawaii and most of Arizona do not observe daylight saving time and therefore do not change their clocks twice a year, according to the Department of Astronomical Applications.
The U.S. territories of American Samoa, Guam, Puerto Rico, the U.S. Virgin Islands and the Northern Mariana Islands also observe permanent standard time, according to the National Conference of State Legislatures.
Do other countries do this?
No. Most countries observe some version of “daylight saving time,” according to the department, and not all follow the same schedule as the United States.
Most Northern Hemisphere countries that observe daylight saving time are located in Europe and North America.
Some countries in the southern hemisphere also observe some version of daylight saving time, but below the equator, the seasons are swapped, so the start and end dates of their “daylight saving time” are reversed from ours.
According to the Pew Research Center, only about a third of all countries observe daylight saving time. About half of all countries observed it at some point but no longer do so.
What efforts have been made to end this practice?
The Senate passed the Sunshine Protection Act in 2022, which would make daylight saving time permanent year-round, but the bill did not advance in the House.
A version of the bill introduced in the Senate in January failed.
Nearly every state has considered legislation to maintain standard or daylight saving time, and 19 states have passed bills or resolutions to implement it year-round in the past seven years, according to the National Conference of State Legislatures. But because federal law does not allow daylight saving time year-round, states would have to wait for Congress to pass the bill to make the change.
What do health experts say?
Some studies suggest that observing daylight saving time year-round could reduce the number of traffic accidents and the number of crimes.
But many experts are not in favor of permanent daylight saving time. This is because, according to sleep experts, the sun should reach the highest point in the sky at noon, which is known as solar time.
Sleep experts prefer moving clocks forward and back over permanent daylight saving time. When people wake up in the dark, hormones like cortisol may be higher, which can make people feel sleepier, Dr. Kin Yuen, a sleep medicine specialist at the University of California, San Francisco and a member of the American Academy of Sleep Medicine, said in 2022.
Then, because the sun rises later, people may go to sleep later during daylight saving time, which can delay the body’s production of melatonin.
