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From 1919 to 2025, 10 moments in Congress's fight over daylight saving time

Congress has tried to stop changing the clocks, and sometimes changed them more. These 10 moments trace a century of daylight saving fights

Congress has spent more than a century deciding whether Americans should move their clocks forward each spring and back each fall, and its answer has changed repeatedly. Calls to stop changing the clocks are not new. Some version of the question has been before Congress since 1918.

The fight began during World War I. The Standard Time Act of 1918 created U.S. time zones and set a wartime daylight saving period. A year later, Congress repealed the daylight saving provision over President Woodrow Wilson's veto. Cities and towns could still keep their own schedules. The result was a patchwork of local clocks that lasted, with a break during World War II, for decades.

Today's rules trace back to the Uniform Time Act of 1966, signed by President Lyndon B. Johnson. It set one national daylight saving period. It also let states opt out and stay on standard time all year, as Arizona, outside the Navajo Nation, and Hawaii do. The law offers no matching path to permanent daylight saving time. A state that wants year-round daylight time needs an act of Congress. That gap is why the Sunshine Protection Act exists.

What follows is a selection of 10 moments, not a complete legislative history. Some were attempts to end the twice-yearly switch. Others ended daylight saving time, imposed it year-round or cut an experiment short, and one simply made the switch uniform. Together they show how often the same question has returned to Washington, D.C., and how rarely the answer has held.

The selection runs from two world wars to the 1973 oil embargo. The embargo prompted a year-round daylight time trial, which Congress cut short in 1974 after complaints about dark winter mornings. From there, the list moves to Florida's 2018 law for permanent daylight time, which takes effect only if Congress allows it. In March 2022, the Senate passed the Sunshine Protection Act by unanimous consent. The House never voted on it. Supporters of the effort to lock the clock have reintroduced the bill since, including in the 119th Congress, which convened in January 2025.

Congress repeals daylight saving time over Wilson's veto in 1919

In 1919, Congress ended federal daylight saving time in the U.S. by overriding President Woodrow Wilson's veto. The repeal came the year after the country first moved its clocks by law. It handed decisions about summer time back to cities and states.

The policy Congress dropped came from the Standard Time Act of 1918. That law did two things. It wrote U.S. time zones into federal law for the first time. It also created a seasonal daylight saving period as a World War I measure.

Under the 1918 law, clocks moved forward in spring and back in fall. The aim was to shift daylight into evening hours and save fuel while the country was at war.

The U.S. was following Europe's lead. Germany introduced daylight saving time in 1916. The U.K. adopted its own version, British Summer Time, later that same year. Before the 1918 law, American time zones rested on a system the railroads had adopted in 1883, not on federal statute.

The war ended in November 1918, and the wartime case for the clock change went with it. Farm interests led much of the opposition. Agricultural work follows sunrise and sunset rather than the clock. Farm groups pressed Congress to scrap the federal schedule.

Congress voted for repeal in 1919. Wilson vetoed it. Lawmakers then overrode the veto in August 1919, and the federal daylight saving provision was gone.

The repeal removed the clock change but left the time zone system in place. The country kept a single national map of time zones. It lost any national rule on when, or whether, clocks should change.

The result was a patchwork. Some cities and states kept daylight saving time on their own, while nearby areas stayed on standard time all year. New York City was among the places that continued to observe it locally.

Apart from World War II, that local patchwork lasted until Congress set nationwide rules decades later. The 1919 repeal was the first time Congress stopped the twice-yearly switch. It did so by ending summer time, not by keeping it all year.

Year-round War Time puts clocks on hold during World War II

During World War II, Congress put the U.S. on daylight time year-round under a policy known as War Time. Clocks moved ahead one hour in early 1942 and stayed there until Sept. 30, 1945. For more than three years, the country had no seasonal clock change.

President Franklin D. Roosevelt signed the measure into law. It was the first federal daylight saving rule since Congress repealed the World War I version in 1919. In the years between, cities and states decided for themselves whether to shift their clocks each spring.

War Time worked differently from the seasonal schedule most Americans know today. Clocks went forward once and did not fall back in autumn. That made it the first nationwide stretch in U.S. history with no twice-yearly switch.

The change also showed up in the names of the time zones. Each zone took a wartime label. The East Coast ran on Eastern War Time, and the Midwest ran on Central War Time. The Mountain and Pacific zones followed the same pattern.

The policy was tied to the war and was not written as permanent law. Its stated purpose was to promote national security and defense. Later evening daylight was intended to cut demand for electricity and fuel at a time of heavy military production.

After Japan surrendered in August 1945, the zones were renamed again, this time as Peace Time. Eastern War Time became Eastern Peace Time, though the clocks themselves did not move. A few weeks later, at the end of........

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