What Time Zone Is Arizona In?
Published May 2026
Arizona occupies one of the most confusing positions on the U.S. time zone map. The state sits inside the Mountain Time zone, but it does not change its clocks for daylight saving time. The result is that for half the year, Arizona shares a clock with Denver, and for the other half it matches Los Angeles. Knowing which is which prevents a lot of missed appointments.
Arizona's Time Zone
Arizona observes Mountain Standard Time (MST), which is UTC-7. This is the same standard time as Denver, Albuquerque, and Salt Lake City. The major difference appears in summer, when those other cities move to Mountain Daylight Time (UTC-6) while Arizona stays put.
MST Explained
Mountain Standard Time is the third zone from the U.S. East Coast. It is two hours behind Eastern Time, one hour behind Central Time, and one hour ahead of Pacific Time during winter. During DST, most MST states briefly become MDT and align with Central Standard Time, but Arizona does not participate in that shift.
The No-DST Rule
Arizona opted out of daylight saving time in 1968. The reasoning was simple: the state already gets intense summer heat and an extra hour of evening daylight would only extend the hottest part of the day. Most residents agreed, and the state has stayed on standard time ever since. The result is a permanent UTC-7 offset year-round.
The Navajo Nation Exception
The Navajo Nation, which spans parts of Arizona, New Mexico, and Utah, does observe daylight saving time across all of its territory. This means that during summer, the Navajo Nation portion of Arizona is one hour ahead of the rest of the state. Travelers driving through the Navajo Nation in summer can effectively cross time zones twice within an hour without leaving Arizona.
Seasonal Comparison Examples
- Winter: Phoenix matches Denver. Phoenix is one hour ahead of Los Angeles.
- Summer: Phoenix matches Los Angeles. Phoenix is one hour behind Denver.
- Year-round: Phoenix is two hours behind New York in winter, three hours behind in summer.
Business and Travel Confusion
Calendar systems sometimes mishandle Arizona because they assume Mountain Time always shifts to MDT. A meeting set in "Mountain Time" with a participant in Phoenix may render an hour off during summer. The safest practice is to set the meeting time zone explicitly to "Arizona" or "Phoenix" rather than relying on a generic Mountain Time label.
Travelers flying into Phoenix from California in winter will lose an hour. The same flight in July arrives at the same local clock time. Always confirm the local time before assuming the offset.
Frequently Asked Questions
Is Arizona on PST or MST?
Arizona is on MST year-round. Because it does not observe DST, its clock matches PST during the summer months.
Does Arizona change clocks?
No. Arizona stays on Mountain Standard Time all year. The only exception is the Navajo Nation, which does observe DST.
Is Phoenix the same time as California?
During DST (March to November), yes. Phoenix and Los Angeles share the same local clock. During winter, Phoenix is one hour ahead.
Why is Arizona different?
The state opted out of DST in 1968 due to the impact of intense summer heat. Adding an hour of evening daylight was considered counterproductive.
Want to learn more? Read about why countries use DST, view the live time in Phoenix, or use the Time Zone Converter to compare other zones.