Prescott uses Mountain Standard Time (MST, UTC−7) throughout the year. Most of Arizona leaves its clocks alone. The Navajo Nation observes daylight saving time; Hawaii stays on standard time too. Arizona State Library
Upcoming U.S. clock changes
- Sunday, November 1, 2026: observing places move clocks back one hour at 2am local time. 2am becomes 1am. Prescott does not change.
- Sunday, March 14, 2027: observing places move clocks forward one hour at 2am local time. 2am becomes 3am. Prescott does not change.
- Sunday, November 7, 2027: observing places move clocks back one hour at 2am local time. 2am becomes 1am. Prescott does not change.
- Sunday, March 12, 2028: observing places move clocks forward one hour at 2am local time. 2am becomes 3am. Prescott does not change.
Under current rules, the spring change is the second Sunday in March; the fall change is the first Sunday in November. NIST time rules
All 50 states
“Changes clocks” means one hour forward in spring and one hour back in fall, following the national dates above. Time-zone boundaries within a state do not change this seasonal rule. U.S. Department of Transportation
| State | Clock rule |
|---|---|
| Alabama | Changes clocks. |
| Alaska | Changes clocks. |
| Arizona | Most areas: no change. Navajo Nation: changes clocks. |
| Arkansas | Changes clocks. |
| California | Changes clocks. |
| Colorado | Changes clocks. |
| Connecticut | Changes clocks. |
| Delaware | Changes clocks. |
| Florida | Changes clocks. |
| Georgia | Changes clocks. |
| Hawaii | No change; standard time all year. |
| Idaho | Changes clocks. |
| Illinois | Changes clocks. |
| Indiana | Changes clocks. |
| Iowa | Changes clocks. |
| Kansas | Changes clocks. |
| Kentucky | Changes clocks. |
| Louisiana | Changes clocks. |
| Maine | Changes clocks. |
| Maryland | Changes clocks. |
| Massachusetts | Changes clocks. |
| Michigan | Changes clocks. |
| Minnesota | Changes clocks. |
| Mississippi | Changes clocks. |
| Missouri | Changes clocks. |
| Montana | Changes clocks. |
| Nebraska | Changes clocks. |
| Nevada | Changes clocks. |
| New Hampshire | Changes clocks. |
| New Jersey | Changes clocks. |
| New Mexico | Changes clocks. |
| New York | Changes clocks. |
| North Carolina | Changes clocks. |
| North Dakota | Changes clocks. |
| Ohio | Changes clocks. |
| Oklahoma | Changes clocks. |
| Oregon | Changes clocks. |
| Pennsylvania | Changes clocks. |
| Rhode Island | Changes clocks. |
| South Carolina | Changes clocks. |
| South Dakota | Changes clocks. |
| Tennessee | Changes clocks. |
| Texas | Changes clocks. |
| Utah | Changes clocks. |
| Vermont | Changes clocks. |
| Virginia | Changes clocks. |
| Washington | Changes clocks. |
| West Virginia | Changes clocks. |
| Wisconsin | Changes clocks. |
| Wyoming | Changes clocks. |
Washington, D.C. changes clocks. American Samoa, Guam, the Northern Mariana Islands, Puerto Rico and the U.S. Virgin Islands do not. DOT exceptions
How daylight saving time came to be
Long before anyone argued about changing clocks in spring, communities kept time by their own local sun. That became awkward when railroads connected towns whose clocks disagreed. In 1883, railroads in the United States and Canada adopted a common system of time zones so timetables could work across long distances. Standard time answered the question of what time it was from place to place; daylight saving later raised a different question: should the clock shift with the seasons? DOT: the origins of standard time
Benjamin Franklin is often credited with inventing daylight saving time, but his 1784 essay was a playful suggestion that Parisians could save candles by getting up earlier. He was proposing a change in habits, rather than a seasonal reset of clocks. A more recognizable proposal came from New Zealand insect enthusiast George Hudson in 1895, who wanted more usable evening daylight. In Britain, William Willett later campaigned for moving the clocks to give people longer light evenings for recreation. The Franklin Institute: Franklin and Hudson; HISTORY: Willett and the early proposals.
World War I turned the idea into national policy. Germany and Austria adopted a one-hour seasonal shift in 1916 to conserve energy, and other countries followed. The United States introduced daylight saving time in 1918, alongside federal recognition of standard time zones. The seasonal requirement was repealed in 1919, while the time zones remained. During World War II, the country returned to continuous daylight time, commonly called “War Time,” from February 1942 through September 1945. HISTORY: wartime adoption; U.S. Naval Observatory: the American timeline.
After World War II, local choices produced an uneven collection of clock-changing rules. The Uniform Time Act of 1966 brought common starting and ending dates, while allowing exemptions. Congress adjusted those dates several times: daylight saving started unusually early during the energy-crisis years of 1974 and 1975, and the spring start moved into early April in 1987. The Energy Policy Act of 2005 established the March-to-November schedule that took effect in 2007. That is why the dates people remember from childhood may differ from the dates used today. U.S. Naval Observatory: changes to the calendar.
Why Arizona keeps its clocks steady
Arizona’s choice became permanent in 1968. Governor Jack Williams signed the state’s standard-time law on March 21, following strong votes in both legislative chambers. In the hotter parts of Arizona, a later sunset by the clock offered less appeal than it did in places eager for longer summer evenings. The state chose to keep Mountain Standard Time throughout the year. Prescott follows that rule, so residents leave their clocks alone even when friends, family and businesses elsewhere change theirs. Arizona State Library: the 1968 decision.
The Navajo Nation observes daylight saving time, keeping its communities in Arizona, New Mexico and Utah on a shared schedule. The Hopi Nation remains on standard time, like most of Arizona. These neighboring rules make it especially useful to confirm the local time when planning a trip through northeastern Arizona. For visitors to Prescott, the practical rule is simple: Prescott stays on MST all year, while its time difference from clock-changing destinations varies with the season. Arizona State Library: Navajo and Hopi time.
Why people still debate the change
Moving the clock redistributes daylight between the morning and evening; it does not add sunlight to the day. The continuing debate weighs brighter evenings against darker mornings, along with questions about energy use and daily routines. There are also two separate choices behind calls to stop changing clocks: permanent standard time and permanent daylight saving time. Under the current federal framework, states may exempt themselves from daylight saving time, but cannot independently choose permanent daylight saving time. A proposal in the news should therefore be distinguished from a rule that has actually taken effect. DOT: what states can choose.
Watch: daylight saving documentaries & explainers
These documentary reports and short educational films explore the story behind the clock change. The publication dates identify when each was made; discussion of proposed legislation reflects that time.
The history of daylight saving time and its effect on our health
A documentary news report tracing the clock-changing tradition and the debate about ending the twice-yearly switch.
PBS NewsHour · November 3, 2022
Watch on YouTube ↗
Daylight Saving Time 101
A short illustrated introduction to the seasonal shift, its intended benefits and its drawbacks.
National Geographic · October 29, 2015
Watch on YouTube ↗
History of Daylight Saving Time
A brief historical overview of how daylight saving time became part of the calendar.
The HISTORY Channel Canada · November 2, 2018
Watch on YouTube ↗