Only two states skip daylight saving time: Hawaii and Arizona. Both stay on standard time all year because their climates make the twice-yearly clock change pointless or counterproductive, and federal law gives every state the right to opt out. Every U.S. territory sits out as well, but among the fifty states, Hawaii and Arizona are the complete list.
The Federal Law That Lets States Opt Out
The Uniform Time Act of 1966 set a national schedule for daylight saving and ended the patchwork of local rules that followed World War II. Under the Act, every state observes daylight saving unless it passes a law exempting itself. The governing provision at 15 U.S.C. § 260a offers two paths: a state entirely within one time zone can exempt itself completely, and a state spanning multiple zones can exempt the whole state or just the portion in a particular zone.1Office of the Law Revision Counsel. 15 USC 260a – Advancement of Time or Changeover Dates
The opt-out runs one way. A state can drop to permanent standard time on its own, but it cannot adopt permanent daylight saving time without an act of Congress. The Department of Transportation oversees uniform time observance and has no authority to approve or deny a state’s choice to opt out.2US Department of Transportation. Uniform Time States that do observe daylight saving must follow the federal start and end dates: the second Sunday in March through the first Sunday in November.
Why Hawaii Doesn’t Observe Daylight Saving
Hawaii’s location in the tropics makes daylight saving irrelevant. The islands sit around 20 degrees north latitude, so the gap between the longest and shortest days of the year is far smaller than on the mainland. Sunrise and sunset shift only modestly across seasons, and pushing clocks forward in spring would barely extend evening light while disrupting morning schedules for no real gain.
Once the Uniform Time Act took effect, the Hawaii State Legislature moved quickly. In 1967 it formally declined to observe daylight saving, keeping the state on Hawaii Standard Time year-round.3US Department of Transportation. Daylight Saving Time The decision has held ever since. One side effect: the time gap with the mainland shifts twice a year. Hawaii is two hours behind Pacific time in winter and three hours behind once the West Coast springs forward.
Why Arizona Doesn’t Observe Daylight Saving
Arizona tried daylight saving once and never went back. When the Uniform Time Act required participation starting in April 1967, Arizona complied. But in a state where summer temperatures regularly top 110°F, an extra hour of evening sun meant air conditioners ran longer, not shorter. Energy consumption climbed instead of falling. Utility bills rose, children played outside in dangerous afternoon heat, and farmers saw no benefit. The legislature abolished daylight saving in 1968, and Arizona has stayed on Mountain Standard Time since.4U.S. Naval Observatory. Daylight Saving Time – Section: History of Daylight Saving Time in the U.S.
Arizona’s situation inverts the original rationale for daylight saving. In northern states, more evening light was supposed to cut the need for electric lighting and heating. In the desert Southwest, the problem isn’t darkness, it’s heat, and more sunlight means more cooling costs.
The Navajo Nation Exception
Arizona’s opt-out isn’t quite statewide. The Navajo Nation, whose territory stretches across northeastern Arizona and into Utah and New Mexico, observes daylight saving to stay synchronized with its communities in those neighboring states. During summer the Navajo Nation runs on Mountain Daylight Time while the rest of Arizona stays on Mountain Standard Time, so you cross a time boundary when you drive onto or off the reservation.
The Hopi reservation adds another wrinkle. It sits entirely surrounded by the Navajo Nation but follows Arizona’s standard time rather than the Navajo schedule. In summer, driving across that part of the state can mean passing through Arizona standard time, Navajo daylight time, Hopi standard time, Navajo daylight time again, and back to Arizona standard time.
U.S. Territories That Also Skip It
Every U.S. territory sits out daylight saving as well. American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands all stay on their respective standard times year-round.3US Department of Transportation. Daylight Saving Time The logic matches Hawaii’s: most sit close enough to the equator that seasonal daylight variation is minimal.
What About States That Want Permanent Daylight Saving?
Roughly 20 states have passed laws or resolutions since 2018 asking for year-round daylight saving time, but none of those states actually observes it. Federal law allows states to opt out of daylight saving, not to adopt it permanently, so those laws cannot take effect without Congress amending or repealing the Uniform Time Act.2US Department of Transportation. Uniform Time Versions of the Sunshine Protection Act that would authorize permanent daylight saving nationwide have been introduced in multiple sessions of Congress and remain stalled.5Congress.gov. S.29 – Sunshine Protection Act of 2025 Until that changes, Hawaii and Arizona remain the only states where clocks don’t move.