Does Arizona Observe Daylight Saving Time?
Most of Arizona does not observe daylight saving time (DST) because the intense desert heat makes an extra hour of evening sunlight undesirable. The only exception is the Navajo Nation, which does follow DST, while the Hopi Reservation inside it does not. The practical result: Arizona is on Mountain Standard Time (MST) in winter, matching Denver, but in summer it effectively aligns with Pacific Time (UTC-7). For the current time in Arizona, see Time.now.
| Season | Arizona (most) | Navajo Nation | New York (ET) | Los Angeles (PT) |
|---|---|---|---|---|
| Winter (Jan) | MST (UTC-7) | MST (UTC-7) | EST (UTC-5) = 2 hours ahead | PST (UTC-8) = 1 hour behind |
| Summer (Jul) | MST (UTC-7) | MDT (UTC-6) | EDT (UTC-4) = 3 hours ahead | PDT (UTC-7) = same |
Why Arizona Opted Out of DST
Arizona last observed DST in 1967, the year after the Uniform Time Act took effect. The state legislature decided that the extra hour of evening daylight would increase energy consumption for air conditioning and extend the already brutal heat. A 1969 study confirmed that DST raised electricity use in Phoenix by 1-4%. The state has remained on MST year-round ever since, a decision supported by residents and businesses. For more on DST across the country, see Daylight Saving Time USA 2026.
The Navajo Nation Exception
The Navajo Nation, which spans parts of Arizona, Utah, and New Mexico, observes DST to keep consistent time with the rest of the Navajo territory outside Arizona. This means that from March to November, the Navajo Nation is one hour ahead of the rest of Arizona. However, the Hopi Reservation, which is entirely surrounded by the Navajo Nation, does not observe DST, creating a "time zone island" within an island. Travelers should be aware of this when visiting the region. For a visual reference, check the US Time Zone Map.
Practical Effects for Residents and Travelers
For most of the year, Arizona's time is straightforward: it is always UTC-7. But during DST (second Sunday in March to first Sunday in November), Arizona matches Pacific Daylight Time (PDT). This means that when it is noon in Phoenix, it is noon in Los Angeles, 1 pm in Denver (which is on MDT), 2 pm in Chicago (CDT), and 3 pm in New York (EDT). For those traveling to Arizona, remember that your devices may automatically switch to DST if they think you are in Mountain Time, so you may need to manually set them to Arizona time. If you are planning a trip, you can check time in Las Vegas for comparison, as Nevada observes DST.
History of Time in Arizona
Arizona has a complex time history. Before 1918, each city set its own time. After the Standard Time Act, Arizona was placed in Mountain Time. The state observed DST briefly during World War I and World War II, and again in 1967 before opting out permanently. In 1973, a bill to reinstate DST failed. Today, Arizona remains one of only two states (with Hawaii) that do not observe DST. For a full list of time zones, see Mountain Time (MT).
Frequently Asked Questions
Does all of Arizona skip daylight saving time?
No. The Navajo Nation in northeastern Arizona observes DST. The rest of Arizona, including Phoenix, Tucson, and Flagstaff, does not.
What time zone is Arizona in?
Arizona is in Mountain Standard Time (MST) year-round, which is UTC-7. During DST, it effectively aligns with Pacific Daylight Time (UTC-7).
Is Arizona on Pacific Time in summer?
Yes, because Pacific Daylight Time is also UTC-7. So from March to November, clocks in Arizona and California show the same time.
Does the Hopi Reservation observe DST?
No. The Hopi Reservation, which lies within the Navajo Nation, does not observe DST, creating a small pocket of MST surrounded by Navajo DST.
Why doesn't Arizona change clocks?
To avoid extra evening heat and increased air conditioning costs. A 1969 study showed DST raised electricity use in Phoenix by 1-4%.
When does DST start and end in the Navajo Nation?
The Navajo Nation follows US DST: starts second Sunday in March, ends first Sunday in November. In 2026, that is March 8 and November 1.