While most of the United States springs forward and falls back each year, the clocks in Arizona and Hawaii have not moved in decades. The story of why these two states—along with several U.S. territories—opted out of daylight saving time is one of climate, geography, and political choice. But it is also, in Arizona’s case, a story of tribal sovereignty: within Arizona’s borders, the Navajo Nation makes its own decision about the clock, observing daylight saving time while the state around it does not. This fascinating patchwork of time zones in the American Southwest reflects deep historical patterns of governance, respect for Indigenous self-determination, and the practical realities of life under a desert sun.
The Origins of Daylight Saving Time in American Law
Daylight saving time (DST) first went into effect in the United States on March 31, 1918, during World War I. The roughly eight-month-long period was designed to provide an extra hour of sunlight in the evenings and was adopted as an energy-saving measure during wartime, when conserving fuel for the war effort was a national priority. It was short-lived: after the war ended, the national mandate was repealed, though some localities continued to observe it on their own.
DST returned nationally during World War II, when the United States observed year-round “war time.” During that same global conflict, Native Americans contributed extensively to the national defense effort—an story explored in depth in our article on how Native Americans protected Alaska during WWII through the Alaska Territorial Guard.
It was only with the passage of the Uniform Time Act of 1966 that daylight saving time permanently took root in federal law, standardizing its observance across states. The current schedule—beginning on the second Sunday in March and ending on the first Sunday in November—was adopted in 2007. Crucially, however, the Uniform Time Act allowed states to exempt themselves entirely from DST observance, provided the entire state stayed on the same standard time. Certain hot and sunny states and territories took immediate advantage of that exemption.
Arizona’s Rejection of Daylight Saving Time
The last time Arizona observed daylight saving time was in 1967. Although the state had adhered to DST during both World Wars along with the rest of the country, Arizonans opted out after the Uniform Time Act took effect—and they never looked back.
The Climate Argument: Why Desert Heat Made DST Unpopular
The primary reason for Arizona’s rejection was the desert climate. “The reason I hear most often is simply that we don’t need another hour of sunlight in the heat of the summer,” meteorologist Jimmy Stewart once explained. At the height of summer, the sun rises in Phoenix around 5:15 a.m. and sets around 8 p.m. Mountain Standard Time. If Arizona observed DST, that sunset would push to nearly 9 p.m., forcing residents to wait until late in the evening to begin outdoor activities without the sun blazing overhead.
A 1969 editorial in the Arizona Republic made the case memorably: “[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. And it’s still hot as blazes!”
There was also a practical energy argument. Data indicated that when the state changed its clocks, energy consumption and cost actually increased—directly contradicting DST’s intended purpose—because air conditioners had to run longer during the extended afternoon heat.
The Navajo Nation Exception: Sovereignty in Time
Arizona’s DST opt-out has one significant exception: the Navajo Nation—whose reservation lands sprawl across Arizona, Utah, and New Mexico—does observe daylight saving time. The Navajo Nation’s decision is a deliberate act of governmental coherence: staying on the same clock as its members in neighboring states keeps Diné communities synchronized across state lines. This choice is a quiet but meaningful expression of the Nation’s governmental authority, a sovereignty the Navajo Nation continues to assert across many domains, as seen in decisions like the Navajo Nation’s ban on genetic research. The result is one of the most unusual timekeeping landscapes in North America: a traveler crossing the Hopi Reservation (which follows Arizona’s MST) into Navajo Nation territory can experience a time change without leaving Arizona.
Hawaii and the Equatorial Clock
Hawaii’s relationship with daylight saving time has been even briefer. The territory tried DST once, in 1933, but the measure lasted only three weeks before being repealed—a remarkably swift rejection. Although Hawaii followed wartime daylight time during World War II alongside the rest of the country, it permanently opted out in 1967 after statehood.
The reason is geographic: Hawaii’s proximity to the equator means sunrise and sunset occur at nearly the same time every day of the year, providing roughly 11 to 13.5 hours of daylight year-round. Shifting the clock would accomplish almost nothing. As Honolulu’s KHON-TV has noted, observing Hawaii Standard Time allows island life to simply follow the flow of the sun.
Other U.S. Territories That Skip the Time Change
Hawaii is not alone among American lands in the Pacific and Caribbean. The U.S. territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands also skip daylight saving time. Like Hawaii, these islands receive abundant sunshine throughout the year, so a twice-yearly clock change would offer minimal benefit. For Indigenous communities across the Pacific—including Native Hawaiians and the CHamoru people of Guam and the Marianas—steady solar timekeeping aligns naturally with traditional rhythms of daily life. To learn more about the diversity of Native American and Indigenous cultures across North America and the Pacific, explore our collection of tribal histories.
The Indiana Comparison
The value of statewide consistency is perhaps best illustrated by Indiana, which switched to statewide DST only in 2006. Before that, the state—already split between the Eastern and Central time zones—observed the time change on a confusing county-by-county basis, which made doing business unnecessarily complicated. Indiana’s eventual standardization underscores the appeal of the uniform approach Arizona and Hawaii took decades earlier.
The Failed Experiment of the 1970s
Interestingly, even the federal government has wavered on permanent DST. During the 1970s energy crisis, Congress briefly enacted year-round daylight saving time as a conservation measure. The experiment was widely regarded as a disaster—particularly in northern states where children walked to school in winter darkness—and it was quickly abandoned. For advocates of ending the clock change entirely, Arizona and Hawaii’s decades of stable timekeeping offer a long-running proof of concept.
Historical Context & Key Cultural Takeaways
- DST was born of wartime necessity: First enacted on March 31, 1918, during World War I, as an energy-conservation measure, and revived during World War II before the Uniform Time Act of 1966 made it the national standard.
- Arizona opted out for climate reasons in 1967: Additional evening sunlight in the Sonoran Desert increased heat exposure and air-conditioning costs—defeating DST’s energy-saving purpose.
- The Navajo Nation exercises timekeeping sovereignty: The Navajo Nation observes DST to stay unified with members in Utah and New Mexico, making an affirmative tribal governmental choice distinct from surrounding Arizona.
- Hawaii’s 1933 experiment lasted three weeks: The islands’ equatorial latitude delivers consistent daylight year-round, so DST offered no benefit. Hawaii formally opted out in 1967.
- Five U.S. territories also decline DST: American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands all remain on standard time year-round.
- The Uniform Time Act permits state exemptions— but tribes, as sovereign nations, navigate time policy on their own terms, producing the remarkable clock mosaic of the American Southwest.
Frequently Asked Questions
When did the United States first adopt daylight saving time?
Daylight saving time first took effect nationally on March 31, 1918, as a World War I energy-saving measure. It was repealed shortly after the war, reinstated during World War II, and permanently standardized under the Uniform Time Act of 1966.
Why doesn’t Arizona observe daylight saving time?
Arizona last observed DST in 1967. The state rejected it primarily due to extreme summer heat: extending daylight into the evening raises temperatures during waking hours, increases air-conditioning costs, and delays comfortable outdoor activity until roughly 9 p.m.
Does the Navajo Nation observe daylight saving time?
Yes. Although most of Arizona remains on Mountain Standard Time year-round, the Navajo Nation observes DST to stay on the same clock as its members in Utah and New Mexico. This creates a unique situation in which parts of northeastern Arizona change their clocks while the rest of the state does not.
Why did Hawaii stop using daylight saving time?
Hawaii tried DST for just three weeks in 1933 before repealing it, followed standard wartime clock changes in World War II, and formally opted out in 1967. Because Hawaii lies close to the equator, the length of daylight barely varies between seasons—making DST pointless.
Which other U.S. territories do not observe daylight saving time?
American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands all skip the time change, remaining on standard time year-round.
Cultural Legacy and Modern Relevance
More than half a century after Arizona and Hawaii first declined to “spring forward,” the debate over daylight saving time continues in statehouses and in Congress. Yet in the desert Southwest, the question of the clock remains more than a matter of convenience—it is a living expression of the layered sovereignty that defines the region. The Navajo Nation’s independent decision to observe DST, distinct from both Arizona and the Hopi Reservation within its boundaries, is a daily reminder that time in Indian Country is not simply dictated by the states that surround tribal lands, any more than tribal nations’ cultural traditions and histories are defined by external borders. For travelers, historians, and anyone fascinated by the intersection of federal law, state policy, and Native sovereignty, the clocks of Arizona and Hawaii tell a story far richer than one hour gained or lost.
