On Sunday, the majority of the U.S. will switch from standard time to daylight saving time, resulting in later sunrises and extended daylight hours across nearly every state. Despite efforts by some lawmakers to establish permanent daylight saving time in the U.S., progress on such legislation has been limited in Congress.

Here’s what to know before the days grow longer.

When is the clock change?

Daylight saving time (DST) will commence on March 10 at 2 a.m. local time. Clocks will advance by one hour.

Standard time commenced on November 5, 2023, at 2 a.m. local time, when clocks were turned back by one hour.

Which states do not observe DST?

With the exception of Hawaii and the majority of Arizona, every state in the U.S. adjusts their clocks biannually to transition between standard time and daylight saving time.

Additionally, American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the Virgin Islands also do not observe daylight saving time.

Why do we have DST?

Initially referred to as "war time" by the Department of Defense, daylight saving time (DST) was introduced through the Standard Time Act in 1918 to extend the daylight hours and reduce energy consumption during World War I.

Although President Wilson initially vetoed the act, it was in effect for approximately eighteen months before being repealed. DST resurfaced as a measure during World War II to curb expenses, and it was reinstated by Congress.

Following the conclusion of World War II in 1945, DST was rescinded, and the topic remained dormant for over two decades. In 1966, the Uniform Time Act was passed by the Department of Transportation to establish standard time within existing time zones, officially enacting DST.

The department explained that a state has the authority to opt out of observing DST by enacting its own legislation. However, states that choose to transition to daylight saving time must do so on the dates mandated by the federal government.

What’s the status of the bill to make DST permanent?

The progress of the bill aimed at making DST permanent at the federal level has been halted in Congress. Despite the Senate's approval of the bill earlier in 2022, it faced obstacles in the House.

Senator Marco Rubio (R-Fla.) reintroduced the Sunshine Protection Act of 2023, which has been introduced to a committee after being read twice. Similarly, Representative Vern Buchanan (R-Fla.) introduced companion legislation, which was also referred to a subcommittee.

“This ritual of changing time twice a year is stupid. Locking the clock has overwhelming bipartisan and popular support. This Congress, I hope that we can finally get this done,” Rubio said in a statement last year.