US Time Zones: Complete Guide to All 6 American Time Zones

The United States spans six primary time zones, covering a spread of 6 hours from the East Coast to Hawaii. This makes the US one of the widest single-country time zone spans in the world. Understanding which zone applies to each state is essential for scheduling calls, flights, and business meetings.

Here is a complete breakdown of all six zones with their UTC offsets and key cities:

*Arizona (except the Navajo Nation) does not observe Daylight Saving Time and permanently stays on MST (UTC−7) year-round.

The Eastern Time Zone is by far the most populous, covering approximately 47% of the US population and hosting the country's financial capital (New York), political capital (Washington D.C.), and numerous major metros. The Pacific Time Zone covers the West Coast tech and entertainment hubs. For a live look at current times, visit the World Clock or check New York time directly.

Two additional territories deserve mention: Puerto Rico observes Atlantic Standard Time (AST, UTC−4) year-round with no DST, and the US Virgin Islands also use AST. Guam uses Chamorro Standard Time (ChST, UTC+10). These are not included in the main six but are part of US jurisdiction.

One of the most common needs when working across the US is quickly knowing what time it currently is in each zone. The offset between the zones is fixed: Eastern is always 1 hour ahead of Central, 2 hours ahead of Mountain, and 3 hours ahead of Pacific — regardless of DST, because all four continental zones observe DST simultaneously.

Use this reference table to convert between zones instantly:

For a live, auto-updating clock for any US city, use the online clock tool. For side-by-side world city comparisons including US zones, the World Clock shows all zones simultaneously.

Note that Alaska is 1 hour behind Pacific, not 2, despite being geographically much farther west. Alaska used to span multiple zones but consolidated into a single statewide zone in 1983 for practical reasons. Hawaii's offset from the mainland is even more dramatic — during standard time Hawaii is 5 hours behind Eastern and 2 hours behind Pacific.

Daylight Saving Time (DST) is observed by most of the United States, but the rules, history, and exceptions are more complex than many people realize. Understanding DST is critical for accurate scheduling, especially when dealing with international partners who may follow different DST schedules.

Current US DST Schedule (Energy Policy Act of 2005):

In 2025, clocks spring forward on March 9 and fall back on November 2. In 2026, the dates are March 8 (spring forward) and November 1 (fall back).

States that do NOT observe DST:

• Arizona (except the Navajo Nation within Arizona): stays on MST (UTC−7) year-round
• Hawaii: stays on HST (UTC−10) year-round

This creates a temporary quirk during the US DST switch period: during winter (standard time), California (PST) is 8 hours behind UTC and 3 hours behind New York (EST). During summer (daylight time), California (PDT, UTC−7) is still 3 hours behind New York (EDT, UTC−4) — the gap stays constant between continental zones because they all switch on the same day.

However, when comparing to Arizona: during summer, Los Angeles (PDT, UTC−7) is only 1 hour behind Phoenix (MST, UTC−7 → wait, Phoenix stays UTC−7), so actually Los Angeles and Phoenix are on the same time during summer months. During winter, Los Angeles (PST, UTC−8) is 1 hour behind Phoenix (MST, UTC−7).

The US has been debating making DST permanent or abolishing it for years. The Sunshine Protection Act passed the Senate in 2022 but did not become law. Until legislation changes, the current schedule remains in effect.

For scheduling calls with Chicago or California, always verify the current offset rather than assuming a fixed number of hours.

If you're calling the United States from another country — or coordinating a US team with international offices — knowing the offset between US time zones and major world cities is essential. The US spans from UTC−5 (Eastern standard) to UTC−10 (Hawaii), making it one of the hardest regions to schedule globally.

Time difference from New York (Eastern Time) to world cities:

Best calling windows from international cities to the US:

For callers in Europe trying to reach the US East Coast: aim for 14:00–17:00 local time (London/Paris), which lands during morning business hours in New York. To reach California from London, 17:00–19:00 London time corresponds to 9:00–11:00 Pacific — the only viable overlap for same-day calls.

For callers in Asia trying to reach the US, the overlap is very limited. Tokyo to New York has a 13–14 hour gap, meaning Tokyo's business day ends while New York's hasn't started. The best window is early Tokyo morning (07:00–09:00) which reaches New York the previous evening (17:00–19:00 EST), or late Tokyo evening (18:00–20:00) which hits New York's morning (04:00–06:00 EST) — workable only if someone starts very early.

For US time zone comparisons with the world, use the World Clock to see all offsets live. For specific East Coast timing, see New York time and for West Coast, see California time.

The 3-hour gap between the East and West coasts creates real scheduling challenges for US businesses. A 9 AM meeting in New York means 6 AM for someone in Los Angeles — before most people's workday begins. Understanding the overlap windows helps teams collaborate more effectively.

Standard US business hours by zone (assuming 9 AM–5 PM local):

The best meeting window for a US-wide all-hands is 1:00–4:00 PM Eastern / 10:00 AM–1:00 PM Pacific. This window includes Alaska and avoids very early morning for the West Coast.

Key US financial markets and their opening times:

• NYSE / NASDAQ (New York): 9:30 AM–4:00 PM Eastern. That's 8:30 AM–3:00 PM Central, 6:30 AM–1:00 PM Pacific.
• CME Group (Chicago): 24-hour futures market, but pit/equity sessions follow similar Central Time hours.
• CBOE (Chicago): 8:30 AM–3:15 PM Central (9:30 AM–4:15 PM Eastern).

For remote workers across zones, the online alarm clock can be set to any US time zone to keep you on schedule. The Chicago time zone page covers Central Time in depth, while New York time covers the Eastern financial hub.