Why Don't All U.S. States Observe Daylight Saving Time?

At 2 a.m. local time on Sunday, November 1, 2026, the clocks in all U.S. states will “fall back” an hour…unless you’re in Hawaii or most of Arizona. The reasons for this are logistical: Hawaii is too close to the equator for the time change to make sense, and Arizona’s climate means changing the clocks would raise energy costs.

Why Daylight Saving Time exists

Daylight Saving Time was first introduced in Germany during World War I to save on energy costs, as working during daylight hours generally requires less energy.

Daylight Saving Time was established in the United States for the same reason in 1918 and was repealed the following year. It was then reinstituted in the U.S. in 1942 during World War II. In the following decades, states were allowed to decide for themselves when to switch from Daylight Saving Time back to Standard Time. After this predictably caused chaos, the Uniform Time Act of 1966 established a standardized Daylight Saving Time schedule across the U.S.

U.S. states have the choice of remaining in standard time permanently or opting into changing their clocks. Indiana opted into the clock-changing ritual in 2006, becoming the 48th state to do so. Still, there are two states that have chosen not to adjust their clocks twice annually.

Why Hawaii and most of Arizona shirk Daylight Saving Time

As of 2026, only two states don’t change their clocks. Hawaii is one, and the reason it doesn’t follow Daylight Saving Time is that it’s located so close to the equator that sunrise and sunset occur around the same time all year. People’s schedules in this state already align with the sun, so it wouldn’t make sense to adjust their clocks. Still, the state tried to do so in 1933 but repealed the measure after just three weeks.

Arizona, meanwhile, avoids Daylight Saving Time due to one reason: the heat. Many residents wait to go outside until the sun sets during the summer because of how hot the days can be. If the state followed Daylight Saving Time, people would have to wait until even later at night to go out and do daily activities—or use even more energy. The state did try to institute Daylight Saving Time in 1967, but that only lasted six months.

“[Data] clearly show that we must wait until about 9 p.m. DST to start any night-time activity such as drive-in movies, moonlight rides, convincing little children it’s bedtime, etc.,” read a 1969 article in the Arizona Republic. “And it’s still hot as blazes!”

There’s one exception: members of Arizona’s Navajo Nation do observe Daylight Saving Time. The reason for this is so their clocks can align with those of fellow members in Utah and New Mexico.

Additionally, the American territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands also do not observe Daylight Saving Time for the same reason as Hawaii: they’re just located too close to the equator for shifting the clocks to make any sense.