Why Arizona and Hawaii Don't Observe Daylight Saving Time
While most Americans adjust their clocks twice a year for daylight saving time (DST), two states-Arizona and Hawaii-do not follow the seasonal time change. When clocks move forward each spring and back again in the fall, residents in these states simply stay on the same time year-round.
The reason comes down largely to geography, climate, and practical considerations.
Daylight saving time was first introduced in the United States during World War I in 1918 as a way to conserve energy by extending daylight hours in the evening. Today, the system remains widely used across the country, but the Uniform Time Act of 1966 allows states to opt out if they choose.
Arizona and Hawaii both took advantage of that option.
Why Arizona Opted Out of Daylight Saving Time
Arizona stopped observing daylight saving time in 1968, mainly because of its desert climate and extremely hot summers.
If the state followed daylight saving time, the extra hour of daylight in the evening would push sunset later into the night. That would keep temperatures high for longer periods and could increase the use of air conditioning, raising energy consumption instead of reducing it.
In cities like Phoenix, summer temperatures often remain above 100°F (38°C) even after sunset. By staying on Mountain Standard Time year-round, Arizona avoids extending those hot daylight hours into the evening.
There is one notable exception within the state. The Navajo Nation, which stretches across parts of Arizona, Utah, and New Mexico, does observe daylight saving time so the entire tribal nation remains on the same schedule.
Why Hawaii Doesn't Change Its Clocks
Hawaii's reason for skipping daylight saving time is very different from Arizona's.
Because the islands sit near the equator, the length of daylight remains relatively consistent throughout the year. Unlike many parts of the mainland United States, sunrise and sunset times in Hawaii change only slightly between seasons.
The state typically experiences between 11 and 13.5 hours of daylight year-round, meaning shifting the clocks forward or backward would provide little practical benefit.
Hawaii briefly experimented with daylight saving time in 1933, but the change lasted only a few weeks before being repealed. When the Uniform Time Act allowed states to opt out, Hawaii officially chose to remain on Hawaii Standard Time all year.
U.S. Territories That Also Skip the Clock Change
In addition to Arizona and Hawaii, several U.S. territories also do not observe daylight saving time.
These include:
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Puerto Rico
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Guam
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American Samoa
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Northern Mariana Islands
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U.S. Virgin Islands
Like Hawaii, many of these locations are closer to the equator, where daylight hours remain fairly stable throughout the year.
Will Daylight Saving Time Ever End Nationwide?
The twice-yearly clock change continues to spark debate in the United States. Some lawmakers and researchers argue the practice disrupts sleep and daily routines, while others believe the extra evening daylight benefits businesses and public safety.
Several proposals-including the Sunshine Protection Act-have aimed to make daylight saving time permanent nationwide, but so far no federal law has ended the clock changes.
For now, most Americans will continue to "spring forward" in March and "fall back" in November, while people in Arizona and Hawaii remain among the few who never need to reset their clocks.
