Time zones
Why Arizona and the Navajo Nation use different summer clocks
Most of Arizona stays on Mountain Standard Time all year, while the Navajo Nation observes daylight saving time: one of North America’s clearest examples of civil time following jurisdiction rather than a state outline.
Arizona opted out
Arizona law keeps the state on standard mountain time rather than adopting the seasonal daylight-saving change used across much of the United States. In practical terms, most of Arizona remains UTC−7 all year, even while nearby states move their clocks.
The Navajo Nation spans three states
The Navajo Nation observes daylight saving time, including its Arizona lands. The Nation explains that sharing a summer clock helps align Diné communities, services and relatives across Arizona, New Mexico and Utah. Geography alone cannot explain this boundary; administration and community links do.
A one-hour surprise for visitors
From spring to autumn, a drive within Arizona can cross from year-round MST into Navajo daylight time, one hour ahead. A meeting, park visit or transport plan therefore needs the named location and date, not simply “Arizona time”.