US Time Zones Explained: All 6 and What States They Cover

The continental United States spans four time zones, Alaska gets a fifth, and Hawaii anchors a sixth. Knowing which states fall where — and the handful of exceptions that don’t follow the obvious pattern — saves real confusion when you’re scheduling across the country.

The Six US Time Zones at a Glance

Time Zone	Standard Offset	Daylight Offset	Abbreviation
Eastern Time	UTC-5 (EST)	UTC-4 (EDT)	ET
Central Time	UTC-6 (CST)	UTC-5 (CDT)	CT
Mountain Time	UTC-7 (MST)	UTC-6 (MDT)	MT
Pacific Time	UTC-8 (PST)	UTC-7 (PDT)	PT
Alaska Time	UTC-9 (AKST)	UTC-8 (AKDT)	AKT
Hawaii-Aleutian Time	UTC-10 (HST)	UTC-9 (HDT)*	HT

*Hawaii itself does not observe daylight saving time and stays at UTC-10 year-round. The Aleutian Islands portion of Alaska does observe DST, which is why the zone is called Hawaii-Aleutian and carries both offsets — but for Hawaii specifically, the daylight offset is never used.

Eastern Time (ET)

Eastern Time covers the northeastern and southeastern US. States entirely within ET include: Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida, Ohio, Michigan (with a small exception in the Upper Peninsula), Indiana (mostly — see below), and the District of Columbia.

UTC offsets: UTC-5 in winter (EST), UTC-4 in summer (EDT).

Indiana’s complicated history: Indiana spent decades with inconsistent DST observance — some counties observed it, some didn’t, and the state’s position on the ET/CT border meant some counties aligned with CT for economic reasons. Indiana fully standardized in 2006, with nearly all counties now on ET and observing DST. A small number of western Indiana counties (around Evansville and near Chicago) are on CT instead of ET.

Central Time (CT)

Central Time covers much of the interior US. States entirely on CT include: Illinois, Wisconsin, Minnesota, Iowa, Missouri, Arkansas, Louisiana, Mississippi, Alabama, Tennessee (most of it), and Oklahoma. Texas is mostly CT, with the westernmost El Paso area on MT.

Parts of several states straddle the CT/ET or CT/MT line. Kansas is primarily CT, though a few western counties observe MT. North and South Dakota each split between CT in the east and MT in the west.

UTC offsets: UTC-6 in winter (CST), UTC-5 in summer (CDT).

A useful mental shortcut: CT is always exactly one hour behind ET. If it’s 3 PM ET, it’s 2 PM CT.

Mountain Time (MT)

Mountain Time covers the Rocky Mountain states and a chunk of the Southwest. States primarily on MT: Montana, Wyoming, Colorado, New Mexico, Utah, and Idaho (most of it).

The Arizona exception: Arizona does not observe daylight saving time. The state remains on Mountain Standard Time (UTC-7) year-round. This means that in summer, when the surrounding states move to UTC-6 (MDT), Arizona is still on UTC-7 — effectively putting it on the same clock as Pacific Daylight Time (also UTC-7). During winter, Arizona and the Mountain states are aligned. During summer, Arizona is one hour behind MT and aligned with PT.

The Navajo Nation, which occupies a large part of northeastern Arizona and extends into Utah and New Mexico, does observe DST and follows MT for the full year. The Hopi Reservation, which is entirely surrounded by the Navajo Nation inside Arizona, follows Arizona’s no-DST rule. This creates an unusual nested zone situation within a small geographic area.

UTC offsets: UTC-7 in winter (MST), UTC-6 in summer (MDT) — except Arizona, which stays at UTC-7 all year.

Pacific Time (PT)

Pacific Time covers the western coastal states: California, Oregon, and Washington. Nevada is on PT, as is most of Idaho’s southern portion (its northern portion is also PT, with the state split along a jagged line).

UTC offsets: UTC-8 in winter (PST), UTC-7 in summer (PDT).

The gap to Eastern Time: New York is 3 hours ahead of Los Angeles during standard time and during daylight time — the gap stays constant at 3 hours throughout the year, because both ET and PT observe DST and move together. This makes ET-to-PT math the easiest cross-US offset to remember.

Alaska Time (AKT)

Alaska uses its own time zone, one hour behind Pacific. This makes practical sense given Alaska’s geographic separation from the rest of the US.

Alaska observes DST. Clocks spring forward and fall back on the same schedule as the other US states.

UTC offsets: UTC-9 in winter (AKST), UTC-8 in summer (AKDT).

A note on the Aleutian Islands: The far western Aleutian Islands (west of 169°30’W longitude) use Hawaii-Aleutian Time rather than Alaska Time, placing them at UTC-10 in winter and UTC-9 in summer. In practice this affects only a very small population in remote areas.

Hawaii-Aleutian Time (HT)

Hawaii uses Hawaii Standard Time (HST) year-round at UTC-10. Hawaii does not observe daylight saving time. There is no HDT for Hawaii — the clocks never change.

UTC offsets: UTC-10 always (for Hawaii).

Because Hawaii doesn’t change clocks, its offset relative to other US zones shifts seasonally. In winter, Hawaii is 5 hours behind Eastern Standard Time. In summer, Hawaii is 6 hours behind Eastern Daylight Time.

Scheduling Across US Time Zones

A few practical notes for US-internal scheduling:

• ET to PT is always a 3-hour gap, year-round.
• ET to CT is always a 1-hour gap. CT to MT is always a 1-hour gap. MT to PT is always a 1-hour gap.
• Arizona in summer is on the same clock as PT (UTC-7), despite being geographically in the Mountain zone.
• Hawaii in summer is 6 hours behind ET and 3 hours behind PT.
• Alaska in summer is 4 hours behind ET and 1 hour behind PT.

For US businesses with offices in multiple regions, the tightest scheduling constraint is usually Hawaii and Alaska. A 9 AM ET standup is 3 AM in Honolulu — before any reasonable working hour. Finding a time that works from coast to coast plus Hawaii often means an afternoon ET call, which pushes toward evening for East Coast participants but remains manageable for Hawaii.

A world clock showing all six US time zones simultaneously makes these tradeoffs immediately visible, without requiring mental arithmetic on each offset.