Which US States Don't Observe Daylight Saving Time?

Arizona (outside the Navajo Nation) and Hawaii are the only two US states that stay on standard time year-round rather than observing daylight saving.

Beyond the two states, five US territories also skip daylight saving entirely: Puerto Rico, the US Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands. All seven — two states and five territories — remain on a single fixed offset all year.

Every other state observes daylight saving under the federal schedule: clocks move forward on the second Sunday in March and back on the first Sunday in November.

Arizona and Hawaii reached their exemptions for different reasons — Arizona to avoid extending its already intense summer heat into the evening, Hawaii because its near-equator daylight barely varies by season — but both rely on the same legal mechanism: the Uniform Time Act of 1966's opt-out provision.

The territories' exemptions were never seriously contested in the same way, since all five sit close enough to the equator that the seasonal daylight swing motivating DST elsewhere barely applies to Puerto Rico, the US Virgin Islands, Guam, American Samoa, or the Northern Mariana Islands.

Together, these seven jurisdictions are the reason no simple rule like 'the whole US observes daylight saving' holds true — any tool or calculation that assumes uniform DST participation across all US states and territories will get Arizona, Hawaii, and every inhabited territory wrong.

A useful way to group them: two states opt out for climate and latitude reasons (Arizona's heat, Hawaii's tropical daylight consistency), while all five territories opt out for the same latitude reason as Hawaii — Puerto Rico, the US Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands all sit close enough to the equator that daylight saving offers little practical benefit.

Everywhere else in the US, including every split-zone state and all of Alaska, follows the same national schedule: clocks move forward on the second Sunday in March and back on the first Sunday in November, with no additional regional exceptions beyond the seven jurisdictions listed here.