Here are all the details to know about daylight saving time and the efforts to end the practice of switching the clocks.

What is daylight saving time?

Daylight saving time lasts for most of the year, typically running from the second Sunday in March to the first Sunday in November. This year, the start and end dates fall on March 8 and Nov. 1, respectively.

At the start of the eight-month period, American citizens set their clocks forward one hour to account for the time change. Then, at the end of it, citizens must set their clocks back one hour. People can know the difference by remembering the famous phrase, “spring forward, fall back.”

The time change is intended to extend more daylight into the evening during the warmer months and provide more daylight in the morning during the colder months.

The switch often disrupts the human circadian rhythm, or internal biological clock, and is linked to risks such as increased heart attacks and car crashes. These factors are why lawmakers have been trying to make daylight saving time permanent for years.

What are the latest efforts to end it?

The Sunshine Protection Act, supported by President Donald Trump, marks the latest effort to end the twice-yearly clock changes.

The bill would require the entire nation to observe daylight saving time, with exceptions for states and territories that do not currently recognize the seasonal time change.

The legislation passed the House Energy and Commerce Committee in a 48-1 vote in May. It is now headed to the House floor for a vote.

The measure was introduced by Rep. Vern Buchanan (R-FL) last year and has 34 cosponsors, mostly Republicans. The Senate has a similar version of the legislation, sponsored by Sen. Rick Scott (R-FL) and 18 cosponsors. One of them, Sen. Tommy Tuberville (R-AL), called on the lower chamber to pass its own legislation.

“Changing our clocks twice a year is an outdated, burdensome practice,” Tuberville posted on X. “I encourage my colleagues in the House to support the Sunshine Protection Act and LOCK THE CLOCK.”

Congress came close to approving a prior version of the Sunshine Protection Act in 2022, when the Senate passed it by unanimous consent. The House, however, did not take up a vote on it at the time.

Some regions have already ditched the switch

While most of the United States recognizes daylight saving time, Hawaii and the majority of Arizona do not and instead observe standard time all year.

Because Hawaii is located close to the equator, its days don’t change very much throughout the four seasons. Meanwhile, Arizona has such a hot climate that it doesn’t make sense for the state to have extra sunlight in the evening.

Both states opted out of daylight saving time in the late 1960s after Congress passed the Uniform Time Act of 1966. The bill instituted daylight saving time nationwide to end chaotic local scheduling.

The U.S. territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands also do not recognize daylight saving time.

When did it start?

Daylight saving time was standardized nationally in 1966, but the system first took hold in the U.S. in 1918, before the end of World War I. It was first implemented by the German and Austro-Hungarian Empires in 1916 as an energy-saving measure during the war.

TRUMP PUSHES TO MAKE DAYLIGHT SAVING TIME PERMANENT AFTER SUNSHINE PROTECTION ACT PASSES COMMITTEE

In 1919, the federal law that enacted daylight saving time was repealed. The time standard was then reestablished during World War II.

Three decades later, President Richard Nixon signed a bill related to daylight saving time into law to save fuel during the 1973 oil crisis.