The DST exemptions in the US — Arizona, Hawaii, and the holdouts

In the US, daylight saving time is mostly observed nationwide — but not entirely. Hawaii, most of Arizona, and several US territories sit out the biannual clock shift. Each has its own reasons. And several other states have laws on the books to abolish DST too, pending federal approval.

For checking US DST dates, the DST calendar shows them. The rest of this post covers the holdouts.

Hawaii — too tropical for DST

Hawaii has been on Hawaii Standard Time (UTC-10) year-round since 1947. The state has never observed DST.

The reasoning is geographic: Hawaii's latitude (~19-22°N) means day length doesn't vary much across seasons. June daylight is about 13.5 hours; December is about 10.8 hours. The benefit of DST — extended evening daylight — is small.

Plus, Hawaii's sunset times are already late by the standards of high-latitude regions. Even in December, sunset is around 5:50 PM. There's not much "evening daylight to gain."

Hawaii's continued non-observance is uncontroversial. No serious DST proposals have surfaced.

Arizona — exemption from federal rule

Arizona has been mostly exempt from DST since 1968. The state had observed DST briefly during World War II and again in 1967 (the year after the federal Uniform Time Act), then exempted itself with a state law in 1968.

The reasoning Arizona cites:

1. Heat. Phoenix and Tucson regularly hit 110-115°F in summer. "More daylight" means "more heat for longer hours." The retail benefit (more evening shopping) is offset by the cost of running A/C an extra hour.

2. Energy use. Arizona's energy demand peaks in summer evenings. DST shifts more activity into peak evening hours, increasing demand on the grid.

3. Cultural preference. Arizona has stayed exempt for over 50 years. The status quo has strong inertia.

Exception within Arizona: the Navajo Nation, a sovereign tribal reservation that extends into Arizona, New Mexico, and Utah, observes DST. So if you're driving through northeastern Arizona in summer, the time on the Navajo reservation is one hour ahead of the surrounding state.

US territories that skip DST

Several US territories don't observe DST:

- Puerto Rico — UTC-4 year-round
- US Virgin Islands — UTC-4 year-round
- Guam — UTC+10 year-round
- Northern Mariana Islands — UTC+10 year-round
- American Samoa — UTC-11 year-round

All are at low latitudes, with the same "tropical, not much benefit" reasoning as Hawaii.

States with permanent-DST laws on the books

Several states have passed laws to switch to permanent DST (year-round summer time), pending federal approval:

- Florida (Sunshine Protection Act, 2018)
- California (Proposition 7, passed 2018)
- Tennessee (2019)
- Mississippi (2021)
- Alabama, Arkansas, Delaware, Georgia, Idaho, Louisiana, Maine, Minnesota, Montana, Ohio, Oklahoma, Oregon, South Carolina, Utah, Washington, Wyoming — various laws passed in the 2010s and 2020s

These laws all share a common provision: they take effect "if and when" Congress allows states to adopt year-round DST without federal coordination. Currently, federal law (Uniform Time Act) requires biannual observance for any state that doesn't fully exempt itself.

States that might exempt themselves entirely

Following Arizona/Hawaii's model — exempt the state from DST but keep standard time year-round — would require:

- State legislation declaring the exemption
- Coordination with the US Department of Transportation (which oversees time zones)

Several states have considered this:

- Massachusetts — multiple proposals over the past decade
- New Hampshire — 2017 study commission, no action
- Vermont — proposals in the legislature
- Minnesota — discussions but no concrete legislation

None has implemented a full exemption like Arizona's.

The federal Sunshine Protection Act

The federal Sunshine Protection Act would lock the entire country onto year-round DST. It has passed the US Senate twice (2022, 2024) by unanimous consent — but failed in the House each time.

Critics of the act argue:

- Health professionals overwhelmingly prefer permanent winter time, not summer time
- Year-round DST means dark mornings in winter, especially northern states
- The 1974 experiment (year-round DST during the energy crisis) was reversed for the same reasons
- The decision to lock in summer time vs winter time has not been adequately debated

If the act ever does pass, US time zones would shift to:
- Eastern: UTC-4 year-round (no winter shift to UTC-5)
- Central: UTC-5 year-round
- Mountain: UTC-6 year-round
- Pacific: UTC-7 year-round
- Arizona, Hawaii, etc.: unchanged

What this means for travelers and meetings

If you're scheduling a meeting:

- Phoenix and Las Vegas, both winter: same time (both at UTC-7). Easy.
- Phoenix and Las Vegas, summer: 1 hour apart (Phoenix at UTC-7, Vegas shifts to UTC-7 from UTC-8). Confusing.
- Phoenix and Denver, both winter: 0 hour difference (Phoenix UTC-7, Denver UTC-7). Easy.
- Phoenix and Denver, summer: 1 hour difference (Phoenix UTC-7, Denver UTC-6). Confusing.

The "Mountain Time" abbreviation is ambiguous in summer because some Mountain Time states observe DST and Arizona doesn't. Specifying "Phoenix time" or "Arizona time" is clearer.

Will Arizona ever adopt DST?

Unlikely. The state has had multiple opportunities and consistently declined. The pattern is stable. The only realistic scenario is federal mandate — and federal mandates on time zones have political resistance.

Will Hawaii?

Even less likely. Hawaii is even more tropical than Arizona, with even less DST benefit. No serious proposals.

FAQ

Why does the Navajo Nation observe DST when Arizona doesn't?

The Navajo Nation is a sovereign tribal entity that exists across multiple states. Its administrative consistency requires using the same time year-round across the reservation. Following the surrounding states' summer DST keeps the reservation aligned with major neighbors.

What about Indian (Native American) reservations elsewhere?

Reservations follow their tribal nation's policy. Some align with surrounding states; some don't. The Navajo Nation is the most prominent example of trans-state alignment.

Has any state ever switched from observing DST to not observing it?

Arizona did, in 1968. Indiana was a complicated case — it observed DST in some counties and not others until 2006, when the state unified. Several Canadian provinces have switched to permanent winter time recently.

Could Florida go to permanent DST without federal approval?

No. Federal law currently requires states observing DST to use the federal schedule. Florida's law would only take effect if federal law changes. The law has been on the books since 2018.

What about Indiana's complicated history?

Until 2006, Indiana had a patchwork: most of the state observed Central Time but not DST; some counties observed Eastern Time with DST. After much confusion, the state unified in 2006 and observes the standard federal DST schedule.

Do any states have permanent winter time?

Hawaii effectively has it (UTC-10 year-round). Most of Arizona has it (UTC-7 year-round). Several Canadian provinces have moved to permanent winter time. No US state has taken the formal step of declaring "we're abolishing DST and locking to standard time," but Arizona's exemption is functionally equivalent.

Bottom line

Hawaii and Arizona are the two main US DST holdouts, both for geographic reasons (latitude making DST benefit minimal). Several states have laws ready to switch to permanent DST pending federal action that hasn't come. The federal landscape is stuck in a debate between permanent summer time (favored by retail and recreation) and permanent winter time (favored by health and education).

For checking what time it is in any specific US state right now, the time-in-United States page shows them.