Pick one clock and keep it

Twice a year, most of the country moves its clocks an hour. Almost nobody likes it. In a Gallup poll from January 2025, fewer than one in five Americans wanted to keep switching. The fight is over which clock to keep.

This site, and this map, assume permanent standard time. That's the clock the sun sets, and it's the one sleep researchers recommend.

A short history of changing the clocks

The 1918 law that created time zones also created daylight saving time, as a wartime measure. It was so unpopular that Congress repealed it the next year. During World War II the country went on year-round daylight saving time, called war time, from February 1942 to September 1945. After the war, states and cities did whatever they wanted, and for twenty years a bus ride could take you through several different clock times.

The Uniform Time Act of 1966 cleaned that up. States that observe daylight saving time all switch on the same dates, and states can opt out and stay on standard time all year. Arizona (except the Navajo Nation) and Hawaii do. What the law doesn't allow is the reverse. No state can go on daylight saving time permanently.

In 2005 Congress stretched daylight saving time, and since 2007 it has run from the second Sunday in March to the first Sunday in November. That's nearly eight months of the year on the clock that's supposed to be the exception.

The time the country tried permanent daylight saving time

It's been tried. During the 1973 oil crisis Congress put the country on daylight saving time year-round to save energy, starting January 6, 1974. In December 1973, 79 percent of Americans supported the idea. By February 1974, after a few weeks of children going to school in the dark, support had dropped to 42 percent. Congress voted to end it, and the country went back to standard time on October 27, 1974, less than ten months in.

What the switch does to people

The spring change takes an hour of sleep from almost everyone on the same night, and the effects show up in hospital and crash data.

A 2019 analysis of seven studies covering more than 115,000 people found the risk of heart attack rose about 5 percent in the days after the spring change. The fall change showed no significant effect.

Researchers at the University of Colorado looked at 22 years of US fatal crash records and found fatal crashes rose about 6 percent in the week after the spring change. That works out to roughly 28 extra deaths a year. The effect was strongest on the western edges of time zones.

Why standard time and not daylight saving time

If everyone agrees the switching should stop, why not keep the summer clock with its late sunsets?

Because mornings matter more. Morning light is what sets the body clock each day. Permanent daylight saving time would mean winter sunrises after 8:00 in much of the country, and after 9:00 in places on the western edges of zones. That's a winter of kids at bus stops in the dark, which is exactly what ended the 1974 experiment.

The American Academy of Sleep Medicine's position, published in 2024, is that the country should end seasonal clock changes in favor of permanent standard time because it fits human biology best. It's joined in that by the National Sleep Foundation, the Sleep Research Society, the Society for Research on Biological Rhythms and Save Standard Time, which together formed the Coalition for Permanent Standard Time.

In Gallup's 2025 poll, Americans who wanted one clock preferred standard time two to one, 48 percent to 24 percent.

Permanent standard time does cost something. Summer sunsets come an hour earlier, around 7:30 in Chicago in June instead of 8:30, and sunrise lands around 4:15. We think that's a fair trade for mornings that aren't dark and a body clock that isn't shoved around twice a year. Not everyone agrees, and that's a real argument.

Where things stand

As of November 2026, the clocks still change. The House passed the Sunshine Protection Act on July 14, 2026, by 308 to 117. That bill would make daylight saving time permanent, the opposite of what the sleep research recommends. It has stalled in the Senate, and the clocks fell back as usual on November 1.

Nineteen states, Florida among them, have passed laws that would put them on permanent daylight saving time if Congress ever allows it. Any state that wants permanent standard time can have it today, without asking Congress, the way Arizona and Hawaii already do.