Arizona Daylight Savings Time traffic sign

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

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a U.S. state, state in the Southwestern United States. It is the list of U.S. states and territories by area, 6th largest and the list of U.S. states and territories by population, 14 ...

is in the

Mountain Time Zone The Mountain Time Zone of North America keeps time by subtracting seven hours from Coordinated Universal Time (UTC) when standard time ( UTC−07:00) is in effect, and by subtracting six hours during daylight saving time ( UTC−06:00). The cl ...

. Since 1968, most of the state—with exceptions noted below—does not observe

daylight saving time Daylight saving time (DST), also referred to as daylight savings time or simply daylight time (United States, Canada, and Australia), and summer time (United Kingdom, European Union, and others), is the practice of advancing clocks (typical ...

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

Unlike most of the United States, Arizona does not observe

(DST), with the exception of the

Navajo Nation The Navajo Nation ( nv, Naabeehó Bináhásdzo), also known as Navajoland, is a Native Americans in the United States, Native American Indian reservation, reservation in the United States. It occupies portions of northeastern Arizona, northwe ...

, 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. 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 .

Reasoning

Because of Arizona's hot climate, DST is largely considered unnecessary. The argument against extending the daylight hours into the evening is that people prefer to do their activities in the cooler morning temperatures. The Navajo Nation, a semi-autonomous Native American territory, follows the United States DST schedule. It lies in northeastern Arizona, northwestern New Mexico, and southeastern Utah and thus maintains the same time throughout tribal lands despite state borders.

Legislative history

On March 21, 1968, the Arizona legislature passed the final version of SB 1, placing Arizona under standard time. 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.

tz database

The

tz database The tz database is a collaborative compilation of information about the world's time zones, primarily intended for use with computer programs and operating systems. Paul Eggert is its current editor and maintainer, with the organizational backi ...

version contains two entries for Arizona:

Example

When daylight saving is not active, the time in Phoenix and Albuquerque, New Mexico is the same (Mountain Standard Time), and both are one hour ahead of

Los Angeles, California Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the wo ...

(Pacific Standard Time). When daylight saving is active, the time in Phoenix (Mountain Standard Time) and Los Angeles (Pacific Daylight Time) is the same, and both are one hour behind Albuquerque (Mountain Daylight Time). The time in Navajo Nation is always the same as in Albuquerque.

References

{{Time in the United States

Geography of Arizona