The Complete Guide to US Time Zones
The United States spans six official time zones, plus additional zones in its territories. Here is the definitive reference for which states fall in which zone, which exceptions apply, and when clocks change in 2026.
Overview: The Six US Time Zones
The contiguous United States (the lower 48 states) uses four time zones. Alaska uses its own zone, and Hawaii has a fifth. Together these six zones cover the 50 states.
| Zone | Abbr (Standard) | Abbr (DST) | Winter (UTC) | Summer (UTC) |
|---|---|---|---|---|
| Eastern | EST | EDT | UTC−5 | UTC−4 |
| Central | CST | CDT | UTC−6 | UTC−5 |
| Mountain | MST | MDT | UTC−7 | UTC−6 |
| Pacific | PST | PDT | UTC−8 | UTC−7 |
| Alaska | AKST | AKDT | UTC−9 | UTC−8 |
| Hawaii | HST | — | UTC−10 | UTC−10 (no DST) |
DST dates for 2026: Clocks spring forward on Sunday, March 8, 2026 at 2:00 AM, and fall back on Sunday, November 1, 2026 at 2:00 AM. Hawaii and most of Arizona do not observe DST.
Eastern Time Zone (EST / EDT)
The Eastern Time Zone is the most populous US timezone, encompassing the major financial, political, and media capitals of the country. It spans the eastern seaboard and extends inland to the Midwest.
Connecticut, Delaware, Georgia, Maine, Maryland, Massachusetts, Michigan (most), New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Vermont, Virginia, West Virginia, District of Columbia, Florida (most).
Indiana: Most of Indiana is Eastern. 12 counties in the northwest (near Chicago) and southwest (near Evansville) observe Central Time.
Kentucky: The western portion of Kentucky (including Bowling Green and the western counties along the Tennessee border) is Central Time. Louisville and Lexington are Eastern.
Tennessee: The eastern portion (Knoxville, Chattanooga) is Eastern; the western portion (Memphis, Nashville) is Central.
Central Time Zone (CST / CDT)
Central Time covers the broad swath of the US midsection, from the Great Plains states through the Gulf Coast.
Alabama, Arkansas, Illinois, Iowa, Louisiana, Minnesota, Mississippi, Missouri, Oklahoma, Wisconsin. Most of Kansas, most of North Dakota, most of South Dakota, most of Nebraska.
Nebraska: The panhandle counties observe Mountain Time. The rest is Central.
North Dakota and South Dakota: The western portions (including Bismarck, ND and most of western SD) observe Mountain Time; the eastern portions are Central.
Kansas: The four southwestern counties (Greeley, Hamilton, Sherman, and Wallace) observe Mountain Time. The rest of the state is Central.
Mountain Time Zone (MST / MDT)
The Mountain Time Zone covers the Rocky Mountain states. It contains one of the most famous timezone anomalies in the US: Arizona.
Colorado, Montana, New Mexico, Utah, Wyoming, most of Arizona, parts of Idaho, parts of Oregon (the southeast corner), parts of South Dakota and North Dakota.
Arizona does not observe Daylight Saving Time. It remains on Mountain Standard Time (UTC−7) year-round, even as neighboring states shift to MDT (UTC−6) in summer. The reasoning: Arizona's hot desert climate makes later sunsets undesirable in summer — people prefer the cooler morning hours.
The Navajo Nation Exception: The Navajo Nation, whose territory spans parts of Arizona, Utah, and New Mexico, does observe DST to maintain consistency across its federally recognized territory. Within Arizona, Navajo Nation lands observe DST while the surrounding state does not — creating a zone-within-a-zone situation.
Practical impact: In winter, Arizona and California are in the same offset (both UTC−8 effectively, since California is on PST). In summer, California springs forward to PDT (UTC−7), matching Arizona. From November to March, Arizona (MST UTC−7) is one hour ahead of Pacific Time (PST UTC−8).
Northern Idaho (including Coeur d'Alene and Moscow) is in the Pacific Time Zone despite the rest of the state being in Mountain Time. This is for economic alignment with Spokane, Washington, directly across the border.
Pacific Time Zone (PST / PDT)
Pacific Time covers the West Coast states and is the home of the US technology industry.
California, Nevada (most), Oregon (most), Washington, and the northern Idaho counties mentioned above. Parts of Oregon (extreme southeast corner near McDermitt) observe Mountain Time.
In winter, Pacific Time (PST, UTC−8) is 3 hours behind Eastern (EST, UTC−5). In summer, PDT (UTC−7) is 3 hours behind EDT (UTC−4). The gap remains constant at 3 hours throughout the year because both zones observe DST on the same schedule.
Alaska and Hawaii
Most of Alaska observes Alaska Standard Time, UTC−9 in winter and UTC−8 (AKDT) in summer. Alaska does observe DST on the standard US schedule. The westernmost Aleutian Islands (west of 169.30° W longitude, including Adak) observe Hawaii-Aleutian Standard Time (HAST, UTC−10), because they lie in a different geographic region.
In winter, Alaska is 4 hours behind New York (EST). During DST (March–November), it is still 4 hours behind EDT, because both zones shift simultaneously.
Hawaii does not observe Daylight Saving Time. It stays on HST (UTC−10) year-round. Hawaii's latitude means that daylight hours vary less than in continental states, making DST less beneficial.
In winter, Hawaii is 5 hours behind Pacific (PST UTC−8). In summer, it becomes 3 hours behind Pacific (PDT UTC−7), because the mainland shifts but Hawaii stays put. Hawaii is always 10 hours behind UTC.
US Territories and Their Time Zones
Puerto Rico does not observe DST and remains on UTC−4 year-round. In winter, it is 1 hour ahead of Eastern time (EST UTC−5). In summer, it aligns with EDT (UTC−4). Home to approximately 3.2 million people.
The US Virgin Islands (St. Thomas, St. John, St. Croix) also use AST year-round without DST, same as Puerto Rico.
Guam is 14–15 hours ahead of US East Coast time, depending on DST. It is the westernmost US territory.
Shares the same timezone as Guam.
American Samoa is one of the last places on Earth to greet the new day, at UTC−11 year-round.
Frequently Asked Questions
When do US clocks change in 2026?
In 2026, US clocks spring forward (standard to DST) on Sunday, March 8, 2026 at 2:00 AM local time. Clocks fall back (DST to standard) on Sunday, November 1, 2026 at 2:00 AM. Hawaii and most of Arizona do not participate.
What time zone is Phoenix, Arizona in?
Phoenix observes Mountain Standard Time (MST, UTC−7) year-round. Arizona does not observe DST. This means Phoenix is the same time as Los Angeles in summer (when California is on PDT/UTC−7) and one hour ahead of Los Angeles in winter (when California is on PST/UTC−8 and Phoenix is still on MST/UTC−7).
How many time zones does the US have in total?
Counting the 50 states: 6 time zones (Eastern, Central, Mountain, Pacific, Alaska, Hawaii). Including US territories: 9 time zones (adding Atlantic/AST for Puerto Rico and USVI, Chamorro/ChST for Guam and CNMI, and Samoa Standard Time for American Samoa). The US spans more time zones than any country except France (which has 12 due to its scattered overseas territories).
What is the difference between EST and EDT?
EST (Eastern Standard Time) is UTC−5 and applies from the first Sunday of November to the second Sunday of March. EDT (Eastern Daylight Time) is UTC−4 and applies from the second Sunday of March to the first Sunday of November. In common speech, "Eastern Time" or "ET" refers to the zone regardless of season. If someone says "5 PM EST" when it's summer, they probably mean EDT — but it's worth clarifying, since the difference is one hour.
Related Tools
Use our Timezone Converter to instantly convert between any US timezone, or the World Clock to see live times across all major US and global cities.