Current Time in US/Arizona Time Zone
IANA Name: US/Arizona
Standard Offset: UTC −07:00
Daylight Saving: No
Currently Observing DST: No ❌
US/Arizona Time Zone: The Permanent Mountain Standard Time Anomaly
The US/Arizona time zone is unique in the United States: it observes Mountain Standard Time (MST) year-round, never shifting to daylight saving time. This means that while most of the Mountain Time zone moves to MDT in summer, Arizona stays at UTC-07:00, creating a seasonal alignment with Pacific Daylight Time and a constant offset from the rest of the region.
Where US/Arizona Applies
This zone covers the entire state of Arizona, including major cities such as Phoenix, Tucson, Mesa, Chandler, Scottsdale, and Flagstaff. The Navajo Nation, which lies partly in Arizona, does observe daylight saving time and uses America/Denver instead. The rest of Arizona uses US/Arizona exclusively.
Offset and Abbreviation
The standard offset is UTC-07:00, abbreviated as MST (Mountain Standard Time). Because there is no daylight saving time, MST is used every day of the year. The abbreviation is constant, unlike zones that switch between MST and MDT.
Daylight Saving Behavior
Arizona opted out of daylight saving time in 1968 under the Uniform Time Act, citing the state's extreme heat: an extra hour of daylight in summer would increase energy use for air conditioning. As a result, the clock never changes. While the rest of the Mountain Time zone springs forward to MDT (UTC-06:00) in March, Arizona remains at UTC-07:00. In winter, Arizona aligns with Denver and other MST areas; in summer, it aligns with Pacific Daylight Time (UTC-07:00), so Phoenix and Los Angeles share the same time from March to November.
Main Countries and Cities
US/Arizona applies only to the United States, specifically the state of Arizona. Key cities: Phoenix (state capital and largest city), Tucson, Mesa, Chandler, Scottsdale, Glendale, and Flagstaff. The zone does not cover any other country, although nearby Hermosillo, Mexico (America/Hermosillo) also uses UTC-07:00 year-round.
Business Hours and Scheduling
When scheduling calls with Arizona, note the seasonal shifts. From March to November, Arizona is on the same time as California (PDT), so a 9 AM meeting in Phoenix is 9 AM in Los Angeles, but 10 AM in Denver (MDT). From November to March, Arizona matches Denver (MST), so 9 AM in Phoenix is 9 AM in Denver but 8 AM in Los Angeles (PST). For international calls: during summer, Arizona is 7 hours behind UTC; in winter, 7 hours behind UTC (no change). For London (UTC+0/UTC+1), Arizona is 7 or 8 hours behind depending on DST in the UK. For Tokyo (UTC+9), Arizona is 16 hours behind in winter and 16 hours behind in summer (since Japan does not observe DST). Always confirm the current offset using a reliable time zone converter.
Why No Daylight Saving?
Arizona's decision was driven by climate and energy considerations. The state's low humidity and intense sun mean that an extra hour of evening daylight would increase air conditioning usage, offsetting any energy savings. Additionally, many businesses and residents prefer consistent schedules year-round. The Navajo Nation, which spans Arizona, Utah, and New Mexico, does observe DST to maintain consistency across its territory, creating a small pocket of different timekeeping within the state.
Comparison with Other Zones at UTC-07:00
Other zones at UTC-07:00 include America/Denver (which uses DST), America/Boise (DST), America/Edmonton (DST), and America/Hermosillo (no DST). The key difference is that US/Arizona stays constant while most others shift. This can cause confusion for travelers and businesses: a flight from Phoenix to Denver in July departs at 2 PM MST and arrives at 4 PM MDT (same local time, but Denver is one hour ahead).
Frequently Asked Questions
Does Arizona ever change its clocks?
No. Arizona does not observe daylight saving time. The entire state (except the Navajo Nation) stays on Mountain Standard Time (UTC-07:00) year-round.
What is the time difference between Arizona and New York?
New York is on Eastern Time. In winter (EST, UTC-05:00), Arizona is 2 hours behind New York. In summer (EDT, UTC-04:00), Arizona is 3 hours behind New York.
Why does the Navajo Nation in Arizona observe daylight saving time?
The Navajo Nation extends into Utah and New Mexico, which observe DST. To keep a uniform time across the entire reservation, the Navajo Nation follows DST, even in the Arizona portion.
Is US/Arizona the same as America/Phoenix?
Yes, America/Phoenix is an alias for US/Arizona. Both refer to the same time zone.
What is the time zone abbreviation for Arizona?
Arizona uses MST (Mountain Standard Time) all year. It never uses MDT (Mountain Daylight Time).
How do I schedule a call with someone in Arizona from Europe?
Check the current offset: Arizona is always UTC-07:00. For example, if you are in London (UTC+0 in winter, UTC+1 in summer), Arizona is 7 or 8 hours behind. Use a time zone converter to find the exact time difference on the day of your call.