Time Zones in the United States: Zones, DST and Exceptions
The United States spans so much of the globe that a single country needs several clocks. Knowing the zones, the daylight saving rules and the exceptions helps you avoid the most common scheduling mistakes.
The main zones
Federal law defines nine standard time zones for the United States and its territories. These six cover the 50 states:
| Zone | Standard time | Daylight saving time | Example city |
|---|---|---|---|
| Eastern | UTC−5 | UTC−4 | New York |
| Central | UTC−6 | UTC−5 | Chicago |
| Mountain | UTC−7 | UTC−6 | Denver |
| Pacific | UTC−8 | UTC−7 | Los Angeles |
| Alaska | UTC−9 | UTC−8 | Anchorage |
| Hawaii–Aleutian | UTC−10 | UTC−9 (Aleutian Islands only) | Honolulu |
The territories use their own zones: Puerto Rico and the US Virgin Islands are on Atlantic Standard Time (UTC−4) all year, Guam and the Northern Mariana Islands are on UTC+10, and American Samoa is on UTC−11.
When the clocks change
Daylight saving time begins at 2:00 a.m. local time on the second Sunday in March and ends at 2:00 a.m. on the first Sunday in November. The change happens at the same local time in each zone, so it rolls across the country over three hours rather than all at once.
Places that do not change their clocks
- Hawaii stays on Hawaii Standard Time all year.
- Most of Arizona stays on Mountain Standard Time all year. The Navajo Nation, in the northeast of the state, does observe daylight saving time. Phoenix therefore matches Los Angeles in summer and Denver in winter. See Phoenix.
- The territories do not use daylight saving time.
States split between two zones
Thirteen states lie in more than one time zone: Alaska, Florida, Idaho, Indiana, Kansas, Kentucky, Michigan, Nebraska, North Dakota, Oregon, South Dakota, Tennessee and Texas. For example, most of Florida is Eastern but the western panhandle is Central, and most of Idaho is Mountain while its northern panhandle is Pacific. Always check the city, not just the state.
Scheduling between the coasts
New York is three hours ahead of Los Angeles all year, because both change their clocks on the same dates. A 09:00–17:00 working day in New York is 06:00–14:00 in Los Angeles, so the shared window is five hours, from 09:00 to 14:00 Pacific time (12:00 to 17:00 Eastern). Many US teams use this as the core meeting window.
When you work with people outside the United States, remember that the US moves its clocks earlier in March and later in November than Europe does. For a few weeks the gap to London or Paris is one hour smaller. Read more in Daylight Saving Time Explained.
Check any US city: search for the city on the World Clock or open its page for the exact offset and daylight saving rules.
Related guides
Time Zones in Europe: WET, CET, EET and the Exceptions
Europe uses three main time zones. Learn which countries use which, when clocks change, and which places, such as Iceland and Turkey, do not follow the pattern.
Time Zones in Asia and the Pacific: A Regional Guide
How time zones work across Asia and Oceania: China and India on one clock, multi-zone countries, half-hour offsets and the few places with daylight saving.
Jet Lag and Time Zones: How to Plan Your Travel
General tips for handling jet lag: why flying east is harder, and how to adjust your sleep and light exposure before and after a trip.