Arizona and Hawaii are the only two U.S. states that do not observe daylight saving time. Both states stay on standard time year-round, meaning residents never “spring forward” or “fall back” with the rest of the country.
The reasons are entirely practical. Arizona’s brutal desert heat makes an extra hour of evening sunlight unwelcome, while Hawaii’s tropical location near the equator means daylight hours barely change between seasons. Understanding why Arizona and Hawaii don’t observe daylight saving time requires a look at American history, climate science, and federal law.
I have spent years researching time zone policy and tracking how every state handles clock changes. Here is a clear, complete breakdown of the history, the legal framework, and the day-to-day reality of living in a state that ignores DST.
Table of Contents
A Brief History of Daylight Saving Time in the US
Daylight saving time first arrived in the United States during World War I. The federal government adopted it in 1918 as an energy-saving measure, following the lead of several European nations that hoped to conserve coal by shifting daylight into evening hours.
The policy was deeply unpopular with farmers, contrary to the popular myth that DST was created for their benefit. Congress repealed it after the war, and for decades the country went back and forth on the practice.
During World War II, President Franklin Roosevelt instituted year-round daylight saving time, calling it “War Time” from 1942 to 1945. Once the war ended, the national mandate disappeared again.
What followed was chaos. From 1945 to 1966, individual cities and states chose their own DST rules. Some towns observed it, neighboring ones did not, and travelers could change their clocks multiple times on a single drive. A bus passenger traveling from Ohio to West Virginia reportedly passed through seven different time changes along a 35-mile stretch.
This patchwork system became so confusing that the federal government stepped in to fix it for good.
The Uniform Time Act of 1966
Congress passed the Uniform Time Act in 1966 to bring order to the mess. The law established a single national daylight saving time schedule, running from the last Sunday in April to the last Sunday in October.
The Act also gave states a legal way out. Any state could exempt itself from daylight saving time by passing its own legislation. This exemption provision is exactly what Arizona and Hawaii used to permanently opt out.
The Department of Transportation was put in charge of overseeing time zones and DST observance. States cannot permanently switch to year-round daylight saving time on their own, but they can choose to stay on standard time. That distinction matters, and it explains why Arizona and Hawaii sit outside the national clock-changing routine.
Why Arizona and Hawaii Don’t Observe Daylight Saving Time
The two states arrived at the same no-DST policy from opposite ends of the climate spectrum. Arizona rejected daylight saving time because of extreme heat. Hawaii rejected it because of geography. Both decisions have held for decades.
Why Arizona Opted Out of Daylight Saving Time
Arizona tried daylight saving time for one summer in 1967, the first year the Uniform Time Act took effect. It was a disaster by nearly every measure.
The problem is the desert climate. Arizona summer temperatures regularly exceed 110 degrees Fahrenheit. Shifting an hour of daylight into the evening meant people ran their air conditioners longer, driving up energy consumption rather than reducing it.
The logic that DST saves energy works in cooler climates where people want more evening light. In Arizona, more evening sun meant more heat in homes and businesses, which meant more electricity burned to cool them back down.
Public backlash was swift. Residents complained that the later sunset pushed outdoor activities into the hottest part of the day. Parents worried about children waiting for school buses in early-morning darkness.
The state legislature acted quickly. In 1968, Arizona passed a law exempting itself from daylight saving time, and voters later reaffirmed that decision through a referendum. The state has stayed on Mountain Standard Time ever since.
One detail worth noting: most of Arizona observes Mountain Standard Time year-round. During the summer months when the rest of the country shifts to daylight time, Arizona effectively aligns with Pacific Time. This is a common source of confusion that I will address later.
Why Hawaii Doesn’t Observe Daylight Saving Time
Hawaii’s reasoning is the opposite of the typical DST rationale. The concept of daylight saving time assumes that shifting clocks can meaningfully redistribute daylight. Near the equator, that assumption falls apart.
Hawaii sits at roughly 19 to 22 degrees north latitude. Because of this tropical location, the length of daylight varies only slightly throughout the year. Sunrise and sunset times shift by less than two hours between summer and winter.
There is simply no daylight to save. Extending evening light by an hour in Hawaii would just mean darker mornings, with no real benefit in return.
Hawaii actually experimented with daylight saving time briefly in 1933, when it was still a U.S. territory. The trial lasted only a few months before being abandoned as pointless. Once Hawaii became a state and the Uniform Time Act passed, Hawaii chose permanent exemption and has never looked back.
The state remains on Hawaii-Aleutian Standard Time all year, making it a steady reference point for anyone coordinating across the Pacific.
The Navajo Nation Exception in Arizona
Arizona’s no-DST policy has one significant wrinkle that trips up travelers. The Navajo Nation, which covers a large portion of northeastern Arizona, does observe daylight saving time.
Because the Navajo Nation spans parts of Arizona, New Mexico, and Utah, tribal leadership chose to keep a uniform time policy across all its territory. Since New Mexico and Utah observe DST, the Navajo Nation follows suit, even within Arizona’s borders.
This creates one of the most unusual time zone situations in the country. Drive through northeastern Arizona in summer, and you may need to change your clock multiple times without ever leaving the state.
It gets more complicated. The Hopi Reservation sits entirely within the Navajo Nation’s Arizona territory. The Hopi Tribe does not observe daylight saving time, following Arizona’s state policy. This means you can enter Navajo land, switch your clock, drive into the Hopi Reservation, switch it back, and then re-enter Navajo land again.
Anyone driving through this region needs to pay close attention to posted signs and local time to avoid showing up an hour early or late.
Other US States and Territories Without Daylight Saving Time
Arizona and Hawaii are the only two states that skip daylight saving time, but they are not alone among U.S. jurisdictions. Five permanently inhabited territories also stay on standard time year-round.
Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands all skip the clock change. Each of these territories sits closer to the equator than the mainland U.S., so the same logic that applies to Hawaii applies to them.
Several other states have passed laws or resolutions attempting to stay on daylight saving time permanently. However, the Uniform Time Act currently prohibits states from adopting year-round daylight saving time without congressional approval. Those efforts remain stalled at the federal level.
Common Misconceptions About Arizona’s Time Zone
The single most common confusion I encounter is about Arizona’s time zone identity. Many people assume Arizona operates on Pacific Time because its clocks match California during the summer.
This is incorrect. Arizona is officially in the Mountain Time Zone. It observes Mountain Standard Time all year and never shifts to Mountain Daylight Time.
The confusion arises because, during DST months, the rest of the Mountain Time Zone shifts one hour ahead while Arizona stays put. That temporarily aligns Arizona with Pacific Daylight Time. Once DST ends in November, Arizona returns to matching the rest of the Mountain Time Zone.
This shifting alignment creates headaches for anyone scheduling calls or meetings. A 9 a.m. meeting that works in March may need adjusting when the clocks change. Businesses operating across state lines learn to track Arizona’s status carefully.
Current Legislative Efforts to Change Daylight Saving Time
The debate over daylight saving time is far from settled. In 2022, the U.S. Senate unanimously passed the Sunshine Protection Act, which would have made daylight saving time permanent nationwide.
The bill stalled in the House of Representatives and never became law. However, support for ending the twice-yearly clock change continues to grow. As of 2026, roughly 20 states have passed legislation or resolutions supporting permanent daylight saving time, pending federal approval.
What would this mean for Arizona and Hawaii? If permanent daylight saving time became federal law, both states would effectively be forced into an hour shift from their current standard time. Arizona would move from Mountain Standard Time to Mountain Daylight Time permanently. Hawaii would shift from Hawaii-Aleutian Standard Time to its daylight equivalent.
Both states have historically resisted such changes, and any federal mandate would likely face pushback from residents who prefer their current arrangement.
Frequently Asked Questions
Why does Arizona not get daylight savings?
Arizona does not observe daylight saving time because its extreme desert heat makes an extra hour of evening sunlight undesirable. Shifting clocks forward increases air conditioning use and energy consumption rather than saving it. Arizona tried DST in 1967, rejected it, and passed a permanent exemption in 1968.
Why doesn’t Hawaii participate in daylight savings time?
Hawaii does not participate in daylight saving time because its location near the equator means daylight hours vary only slightly throughout the year. There is little to no benefit to shifting clocks. Hawaii briefly tried DST in 1933 and abandoned it after a few months.
What are the two states that don’t do daylight savings?
Arizona and Hawaii are the only two U.S. states that do not observe daylight saving time. Both states stay on standard time year-round. Several U.S. territories including Puerto Rico, Guam, and American Samoa also skip DST.
Can states opt out of daylight savings time?
Yes. Under the Uniform Time Act of 1966, any state can exempt itself from daylight saving time by passing state legislation. States cannot switch to permanent daylight saving time without congressional approval, but they can choose to remain on standard time indefinitely.
Conclusion
The reasons why Arizona and Hawaii don’t observe daylight saving time come down to climate and geography. Arizona’s desert heat makes extra evening daylight a burden, while Hawaii’s equatorial position renders clock changes pointless.
The Uniform Time Act gave both states the legal mechanism to opt out, and decades of experience have validated those decisions. If you are traveling to either state or coordinating across time zones, remember that Arizona and Hawaii hold steady while the rest of the country shifts twice a year.