Why Do We Change the Clocks? (And Is Daylight Saving Time Ending?)

Part 1

When Does Daylight Saving Time End in 2026?

Daylight saving time ends on Sunday, November 1, 2026, at 2:00 a.m. local time. At that moment clocks go back one hour to 1:00 a.m., so the hour between 1 and 2 a.m. happens twice and you get an extra hour of sleep ^[1].

The rule has been the same since 2007: daylight saving time starts on the second Sunday in March and ends on the first Sunday in November. Congress set those dates in the Energy Policy Act of 2005 ^[1]. That means the next change is Sunday, March 14, 2027, when clocks spring forward and you lose an hour.

The easy way to remember which way to go: spring forward, fall back.

• Changes by itself: smartphones, computers, smartwatches and most cable boxes.
• Usually needs you: ovens, microwaves, car dashboards, older alarm clocks and wall clocks.
• Worth checking: thermostats, coffee makers and security cameras with schedules.

Part 2

Was Daylight Saving Time Created for Farmers?

No. This is the most repeated myth about the time change, and it's backwards. Farm work runs on the sun, not the clock. Cows need milking at the same point in their day whatever the clock says, and moving the clock an hour later meant losing a morning hour that farmers used to get crops to market.

The Library of Congress notes that the agriculture industry "fervently opposed" the change, and that farm groups lobbied Congress to repeal it ^[2]. They won. Congress repealed national daylight saving time in 1919, overriding President Woodrow Wilson's veto to do it ^{[2, 3]}.

Part 3

Why Was Daylight Saving Time Started?

Daylight saving time was a wartime energy measure. In 1916, Germany began observing it to conserve fuel, and much of Europe soon followed ^[3]. The idea was simple: if clocks are an hour later in summer, people are awake during more of the evening daylight, so they burn less coal and oil for lighting.

The United States adopted it on March 31, 1918, in the same law that created the country's standard time zones ^{[2, 3]}. After the 1919 repeal, it came back nationally during World War Two as year-round "War Time," which lasted from 1942 until September 30, 1945 ^[3]. For two decades after the war, each state and city chose for itself, which caused a patchwork of clocks. The Uniform Time Act of 1966 finally set one national schedule, and let states opt out as long as the whole state did so ^[3].

Part 4

Has the US Ever Had Daylight Saving Time All Year?

Yes, twice. The first was War Time in the 1940s. The second was a peacetime experiment during the 1970s energy crisis. On January 6, 1974, the country switched to daylight saving time year-round under an emergency law meant to last until 1975 ^[3].

At first it was popular. In December 1973, 79% of Americans supported the idea. By February 1974, after a few weeks of pitch-dark winter mornings, support had dropped to 42% ^[4]. Children were heading to school before sunrise, and some schools pushed back their start times ^[4]. In October 1974, President Gerald Ford signed a law ending the experiment early, and standard time returned on October 27, 1974 ^{[4, 3]}.

Part 5

Which States Don't Observe Daylight Saving Time?

Under the 1966 law, a state can stay on standard time all year, but it can't adopt daylight time all year without Congress changing the law ^[3]. Two states have opted out: Hawaii, since 1967, and Arizona, since 1968 ^[3]. Hawaii is close enough to the equator that its days change length much less than on the mainland, and in Arizona's desert heat, an extra hour of evening sun is the last thing most people want.

Arizona has its own exception. The Navajo Nation, which covers part of northeastern Arizona, does observe daylight saving time, so in summer the clock can change as you drive across the reservation ^[3].

Around the world, changing the clocks is the exception. About 70 countries use daylight saving time in 2026. That's less than 40% of the world's countries, and many others have tried it and stopped ^[9].

Part 6

How Does the Time Change Affect Your Body?

Your body runs on an internal clock, your circadian rhythm, that takes its cues mainly from light. When the clock on the wall jumps by an hour, your body clock doesn't, so for a few days you may wake too early, feel sleepy at odd times or have trouble falling asleep. This is general information, not medical advice.

Researchers have found that the spring change, when we lose an hour, is the hard one. The fall change is gentler, and some measures even improve for a day or two.

“Our results support the theory that abolishing time changes completely would improve public health.”

One detail is easy to miss. In the heart attack study, the total number of heart attacks that week didn't change, only the timing ^[8]. That suggests the lost hour mostly shifts when heart attacks happen rather than causing more of them overall.

To make the fall change easy: keep your usual wake-up time on Sunday instead of sleeping in, get some daylight soon after you wake up, and go to bed at your normal clock time. If 3 a.m. wake-ups are already your problem, our explainer on why you keep waking up at 3 AM covers the most common causes.

Part 7

Is Daylight Saving Time Ending? Where the Sunshine Protection Act Stands

Not yet. On July 14, 2026, the House of Representatives passed H.R. 139, the Sunshine Protection Act, by 308 votes to 117 ^[5]. The bill would end the twice-a-year switch by keeping daylight saving time all year.

The vote crossed party lines. Most Republicans and just over half of Democrats voted yes ^[5]:

A bill needs to pass both chambers and be signed by the president to become law. As of early October 2026, the Senate had not voted on it. President Trump publicly urged the Senate to hold a vote and said Senator Tom Cotton was holding the bill up ^[10]. Until something passes, the switch on November 1 goes ahead as normal.

This isn't the first time it got this far. The Senate passed an earlier version of the Sunshine Protection Act by unanimous consent in 2022, but the House never voted on it, so it died ^[11].

Part 8

Permanent Daylight Time or Permanent Standard Time?

Almost everyone agrees the switching is a hassle. The real fight is over which time to keep, and they're opposites.

Permanent daylight time, what the Sunshine Protection Act would do, means brighter evenings all year. That's good for after-work errands, sports and shopping. The cost is very dark winter mornings, the same problem that sank the 1974 experiment.

Permanent standard time means brighter winter mornings and earlier sunsets. This is what many sleep scientists prefer. The American Academy of Sleep Medicine says the US should "eliminate seasonal time changes in favor of permanent standard time," because morning light helps keep your body clock in sync ^[6].

“Permanent standard time helps synchronize the body clock with the rising and setting of the sun.”

Times in the table were calculated by Mustard Explains for the winter solstice using NOAA's solar formulas (the same ones the tool below uses), so they may differ from a weather app by a minute. Under permanent daylight time, the sun wouldn't rise in Detroit until nearly 9 a.m. in late December.