Most Americans should consider going to bed early Saturday night, because they are about to lose an hour of sleep.

Daylight saving time is imminent, meaning that on Sunday, 2 a.m. will become 3 a.m. in the matter of a seconds. On the bright side, the “spring forward” will delay when day becomes night leading to sunnier drives home from work for many.

The new time schedule will go until November, when standard time returns ahead of the holiday season.

Here’s what to know about “spring forward” this weekend, including when the process began, which two states are exempt from it and efforts to end time changes permanently.

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When does daylight saving time start?

Daylight saving time begins on Sunday, March 9 at 2 a.m. local time.

What is daylight saving time?

Daylight saving time is the time between March and November when most Americans adjust their clocks ahead by one hour.

We lose an hour in March (as opposed to gaining an hour in the fall) to make for more daylight in the summer evenings. In the Northern Hemisphere, the vernal, or spring equinox, is on March 20, marking the start of the spring season.

When does daylight saving time end?

Daylight saving time ends for the year on Sunday, Nov. 2.

Which states don’t observe daylight saving time?

Hawaii and most of Arizona do not observe daylight saving time. Because of its desert climate, Arizona doesn’t follow daylight saving time (with the exception of the Navajo Nation). After most of the U.S. adopted the Uniform Time Act, the state figured that there wasn’t a good reason to adjust clocks to make sunset occur an hour later during the hottest months of the year.

When did federal time changes start?

The Standard Time Act of 1918 was the first law to implement standard and daylight saving times at the federal level.

“Federal oversight of time zones began in 1918 with the enactment of the Standard Time Act, which vested the Interstate Commerce Commission with the responsibility for establishing boundaries between the standard time zones in the U.S.,” according to The U.S. Department of Transportation. “This responsibility was transferred from the Interstate Commerce Commission to DOT when Congress created DOT in 1966.”

Who is in charge of daylight saving time?

The DOT oversees the observance of daylight saving time, as well as U.S. time zones, according to the federal agency. The DOT cited energy reduction and reduced crime as reasons for having both standard and daylight saving time.

Is daylight saving time ending?

Recent bills that would make daylight saving time the national year-round standard have languished in committee after being introduced in January.

Officials have vowed to put an end to the procedure, including President Donald Trump, who said in a Truth Social post in December that “the Republican Party will use its best efforts to eliminate daylight saving time.”

However, since resuming office for his second term in January, the president has not issued any executive orders on the issue. Congress, which has a narrow GOP majority, has also not shown a major push on the issue.

Contributing: Alexis Simmerman, Jana Hayes, The Oklahoman, James Powel, Emily DeLetter, Jennifer Sangalang, USA TODAY Network.