Home / Guides / Why Arizona doesn't change its clocks
Why Arizona Doesn't Change Its Clocks (and the One Part That Does)
While most of the United States moves its clocks twice a year, Arizona doesn't. Since 1968 almost the whole state has stayed on Mountain Standard Time (MST, UTC−7) all year round. It is one of the most common reasons people get a meeting or a flight time wrong.
The short history
The federal Uniform Time Act of 1966 set national rules for daylight saving time, but it allowed a state to exempt itself and stay on standard time. Arizona tried daylight saving time in 1967 and didn't like it. In 1968 the state legislature voted to opt out, and it has stayed that way ever since. Hawaii is the only other state that doesn't use daylight saving time.
Why it makes sense there
The point of daylight saving time is to give people more usable daylight in the evening. In Phoenix, summer evenings are not something people want more of. Afternoon temperatures regularly pass 105°F (40°C), and the sun setting an hour later would mean an extra hour of heat before it cools down, plus more air-conditioning use. Arizona is also far enough south that its days don't stretch out as much as they do in northern states.
So what time is it in Arizona?
Because Arizona stays put while its neighbors move, its relationship to them flips twice a year:
| Compared with | Mid-March to early November | Early November to mid-March |
|---|---|---|
| California (Pacific) | Same time | Arizona is 1 hour ahead |
| Denver (Mountain) | Arizona is 1 hour behind | Same time |
| Chicago (Central) | Arizona is 2 hours behind | Arizona is 1 hour behind |
| New York (Eastern) | Arizona is 3 hours behind | Arizona is 2 hours behind |
An easy way to remember it: in summer Arizona lines up with California, and in winter it lines up with Colorado. You can check the current time on the Phoenix time page or the Arizona time zone page.
The exception: the Navajo Nation
The Navajo Nation covers a large area of northeastern Arizona and also reaches into Utah and New Mexico, which both use daylight saving time. To keep one time across its whole territory, the Navajo Nation does use daylight saving time, including the parts inside Arizona.
To make it more confusing, the Hopi Reservation sits entirely inside the Navajo Nation, and the Hopi follow Arizona's rule and don't change. So in summer you can drive from Arizona time into Navajo time, into Hopi time, and back into Navajo time within an hour or two.
What this means in practice
- Flights: airline schedules always show local time at each airport, so a flight from Phoenix to Los Angeles in July may show the same departure and arrival hour as its flight length.
- TV and sports: a show listed as "8/7 Central" airs at a different Arizona time in summer than in winter.
- Phones: your phone handles all of this automatically, as long as it is set to update the time zone by location. Near the Navajo Nation border, phones sometimes pick up a tower on the other side and show the wrong hour.
Quick answers
Is Arizona on Pacific or Mountain time?
Mountain Standard Time, all year. In summer that happens to match Pacific Daylight Time, which is why Arizona has the same time as California from March to November.
Does the Navajo Nation observe daylight saving time?
Yes. The Navajo Nation, including its land in Arizona, moves its clocks with Utah and New Mexico. The Hopi Reservation inside it does not.
Which other US state doesn't change its clocks?
Hawaii. US territories such as Puerto Rico and Guam don't change either.
Spotted a mistake? Let us know and we'll fix it.