US Time Zones Guide
Everything you need to know about Eastern, Central, Mountain, and Pacific time zones across the United States
The United States spans a vast geographic area, stretching from the Atlantic Ocean to the Pacific. To keep local time aligned with the sun's position, the US uses six time zones. The contiguous 48 states are divided into four main zones: Eastern, Central, Mountain, and Pacific. Alaska and Hawaii-Hawaii-Aleutian each have their own. Understanding how these zones work is essential for scheduling meetings, traveling, and coordinating across state lines.
The Four Main US Time Zones
Each zone is approximately one hour apart from its neighbor. When it is noon on the East Coast, it is 11:00 AM in the Central zone, 10:00 AM in the Mountain zone, and 9:00 AM on the West Coast. During daylight saving time, all four zones shift forward by one hour, so the relative differences stay the same.
Eastern Time (ET)
Eastern Time is the most populous time zone in the US, covering roughly half the country's population. During standard time, Eastern Standard Time (EST) is UTC-5. During daylight saving time, it becomes Eastern Daylight Time (EDT) at UTC-4. Eastern Time is used in states along the entire East Coast plus many inland states.
States in Eastern Time
- CT Connecticut
- DE Delaware
- FL Florida (most of state)
- GA Georgia
- IN Indiana (most of state)
- ME Maine
- MD Maryland
- MA Massachusetts
- MI Michigan (most of state)
- NH New Hampshire
- NJ New Jersey
- NY New York
- NC North Carolina
- OH Ohio
- PA Pennsylvania
- RI Rhode Island
- SC South Carolina
- VT Vermont
- VA Virginia
- WV West Virginia
- DC Washington, D.C.
Central Time (CT)
Central Time covers the middle portion of the country and is the second most populous zone. Central Standard Time (CST) is UTC-6, while Central Daylight Time (CDT) is UTC-5. Many major cities including Chicago, Houston, and Dallas operate on Central Time.
States in Central Time
- AL Alabama
- AR Arkansas
- IL Illinois
- IA Iowa
- KS Kansas (most of state)
- KY Kentucky (western part)
- LA Louisiana
- MN Minnesota
- MS Mississippi
- MO Missouri
- NE Nebraska (most of state)
- ND North Dakota (most of state)
- OK Oklahoma
- SD South Dakota (most of state)
- TN Tennessee (western part)
- TX Texas (most of state)
- WI Wisconsin
Mountain Time (MT)
Mountain Time occupies the Rocky Mountain region and the Great Plains. Mountain Standard Time (MST) is UTC-7, and Mountain Daylight Time (MDT) is UTC-6. This zone is notable because Arizona does not observe daylight saving time, keeping MST year-round, while the rest of the zone shifts during summer.
States in Mountain Time
- AZ Arizona (no DST)
- CO Colorado
- MT Montana
- NM New Mexico
- UT Utah
- WY Wyoming
- ID Idaho (southern part)
Pacific Time (PT)
Pacific Time covers the West Coast and is the zone most associated with Hollywood, Silicon Valley, and Seattle's tech industry. Pacific Standard Time (PST) is UTC-8, and Pacific Daylight Time (PDT) is UTC-7. It is the zone most Americans think of when they hear "West Coast time."
States in Pacific Time
- CA California
- OR Oregon (most of state)
- WA Washington
- NV Nevada (most of state)
- ID Idaho (northern panhandle)
Alaska and Hawaii Time Zones
Beyond the contiguous 48 states, the US has two additional time zones. Alaska Time (AKST/AKDT) is UTC-9/UTC-8, covering the majority of the state. The Aleutian Islands in far western Alaska use Hawaii-Aleutian Time. Hawaii does not observe daylight saving time and remains on Hawaii-Aleutian Standard Time (HST) at UTC-10 year-round.
Daylight Saving Time Rules
All US time zones observe daylight saving time except Hawaii and most of Arizona. In 2007, the Energy Policy Act changed the DST schedule: clocks spring forward on the second Sunday in March at 2:00 AM and fall back on the first Sunday in November at 2:00 AM. This extended DST by about a month compared to the previous schedule.
Key DST Facts
DST shifts each zone by exactly one hour. The relative difference between zones never changes. When the East Coast springs forward to EDT (UTC-4), the West Coast springs forward to PDT (UTC-7). The 3-hour gap between them stays constant throughout the year.
Arizona stays on Mountain Standard Time (UTC-7) all year, meaning it matches Pacific Daylight Time during summer months. Hawaii stays on HST (UTC-10) year-round, making it 5 hours behind the East Coast during standard time and 6 hours behind during DST.
Time Differences at a Glance
| Zone | Standard | Daylight | Offset | Example City |
|---|---|---|---|---|
| Eastern | EST | EDT | UTC-5 / UTC-4 | New York City |
| Central | CST | CDT | UTC-6 / UTC-5 | Chicago |
| Mountain | MST | MDT | UTC-7 / UTC-6 | Denver |
| Pacific | PST | PDT | UTC-8 / UTC-7 | Los Angeles |
When New York is at 3:00 PM Eastern, Chicago is at 2:00 PM Central, Denver is at 1:00 PM Mountain, and Los Angeles is at 12:00 PM Pacific. Use a time zone converter to quickly check differences for any US city.
State Boundaries and Time Zone Splits
Several US states are split between two time zones. This creates practical challenges for residents, businesses, and local governments. Indiana is one of the most well-known examples, with counties in both Eastern and Central Time. Kentucky, Tennessee, North Dakota, South Dakota, Nebraska, Kansas, and Florida also have zones that straddle the state line.
The boundaries were determined by the Department of Transportation in 1983 based on factors such as commerce patterns, communication, and transportation networks. Changes require federal approval and typically involve input from state and local governments. The process can take years, as communities on either side of a proposed change often have strong and conflicting opinions.
Frequently Asked Questions
How many time zones does the US have?
The US has 6 time zones: Eastern, Central, Mountain, Pacific, Alaska, and Hawaii-Aleutian. The contiguous 48 states use 4 main zones, while Alaska and Hawaii each have their own. Some territories also have their own zones, including Atlantic Time in Puerto Rico and the US Virgin Islands.
What states are in each US time zone?
Eastern Time covers the East Coast including New York, Florida, and Georgia. Central Time includes Texas, Illinois, and most of the Midwest. Mountain Time covers Colorado, Montana, Utah, and surrounding states. Pacific Time includes California, Oregon, and Washington. Some states are split between two zones.
Does Arizona observe daylight saving time?
Most of Arizona does not observe DST, staying on Mountain Standard Time (UTC-7) year-round. The Navajo Nation within Arizona does observe DST to stay aligned with neighboring Utah and New Mexico. This creates an unusual situation where the state effectively has two different time behaviors depending on location.
What is the time difference between East Coast and West Coast?
The East Coast (Eastern Time) is 3 hours ahead of the West Coast (Pacific Time) during both standard and daylight saving time. Since both zones shift forward by 1 hour during DST, the 3-hour difference between them remains constant year-round.
Explore Related Topics: US Time Now | Daylight Saving Time | Time Zone Abbreviations | Time Zone Converter