Time in Arizona


Time in Arizona, as in all U.S. states, is regulated by the United States Department of Transportation[1] as well as by state and tribal law.

All of Arizona is in the Mountain Time Zone.[2] Since 1968, most of the state—with exceptions noted below—does not observe daylight saving time and remains on Mountain Standard Time (MST) all year. This results in most of Arizona having the same time as neighboring California each year from March to November, when locations in the Pacific Time Zone observe daylight saving time.

Daylight saving time


Daylight saving time in Arizona. DST regions are colored yellow.

Unlike most of the United States, Arizona does not observe daylight saving time (DST), with the exception of the Navajo Nation, which does observe DST. The Hopi Reservation, which is not part of the Navajo Nation but is geographically surrounded by it, also does not observe DST.[2] For this reason, driving the length of Arizona State Route 264 east from Tuba City while DST is in place involves six time zone changes in less than 100 miles (160 km).

On March 21, 1968, the Arizona legislature passed the final version of SB 1, placing Arizona under standard time.[3]:629[4] The bill had been working its way through the legislature since January of that year, and was sponsored by state Senators Tenney, Goetze, Porter, Halacy, Garfield, Campbell, Lewis, Gregovich, Giss, Crowley, and Holsclaw. It passed the Senate 25–3–2, and afterwards the bill was passed by the House 49–1–10. It was approved by Governor Jack Williams the same day.[4]

The tz database version 2021a contains two entries for Arizona:

CC Coordinates TZ Comments UTC offset UTC offset DST Notes
US +332654−1120424 America/Phoenix MST - Arizona (except Navajo) −07:00 −07:00
US America/Shiprock −07:00 −06:00

Example

When daylight saving is not active, the time in Phoenix and Denver is the same (Mountain Standard Time), and both are one hour ahead of San Diego (Pacific Standard Time).

When daylight saving is active, the time in Phoenix (Mountain Standard Time) and San Diego (Pacific Daylight Time) is the same, and both are one hour behind Denver (Mountain Daylight Time).

The time in Navajo Nation is always the same as in Denver.

Example times
 CaliforniaArizonaColoradoRef.
San DiegoPhoenixNavajo NationDenver
Standard time (winter)1 p.m. PST2 p.m. MST2 p.m. MST2 p.m. MST[5]
Daylight time (summer)2 p.m. PDT2 p.m. MST3 p.m. MDT3 p.m. MDT[6]

References


  1. "Uniform Time". US Department of Transportation. 13 February 2015. Archived from the original on 24 August 2018. Retrieved 24 August 2018. The U.S. Department of Transportation (DOT) oversees the Nation's time zones and the uniform observance of Daylight Saving Time. The oversight of time zones was assigned to DOT because time standards are important for many modes of transportation.
  2. "Time Zones in Arizona, United States". timeanddate.com. Retrieved March 9, 2019.
  3. "Session laws, State of Arizona, 1968, Twenty-Eighth Legislature, Second Regular Session, Second to Fourth Special Sessions". State of Arizona. Retrieved October 13, 2018.
  4. "Journal of the Senate, State of Arizona, 1968, Twenty-Eighth Legislature, Second Regular Session, Fourth Special Session". Arizona Memory Project. 1968. p. 740.
  5. "The World Clock Meeting Planner for March 1, 2019". timeanddate.com. Retrieved March 9, 2019.
  6. "The World Clock Meeting Planner for April 1, 2019". timeanddate.com. Retrieved March 9, 2019.