What each live clock displays
Six clocks run simultaneously, one for each main US time zone. Every clock shows three pieces of information:
- The current local time, advancing second by second.
- The current UTC offset (for example, UTC−4 for Eastern Daylight Time).
- The DST status: "Daylight Time" or "Standard Time".
The six zones and their typical year-round offsets:
| Zone | Standard Offset (UTC) | Daylight Offset (UTC) |
|---|---|---|
| Eastern | −5 | −4 |
| Central | −6 | −5 |
| Mountain | −7 | −6 |
| Pacific | −8 | −7 |
| Alaska | −9 | −8 |
| Hawaii-Aleutian | −10 | −9 (Hawaii does not observe DST, so always −10) |
Hawaii and most of Arizona never change their clocks. The Navajo Nation in Arizona does observe DST. The live clocks handle this automatically.
How to read the current US time display
The clock for each zone shows a three-letter abbreviation: EDT, CDT, MDT, PDT, AKDT, HST. That abbreviation tells you the current rule.
- ET / CT / MT / PT are umbrella terms. They do not tell you whether DST is in effect. Use the abbreviation on the clock instead.
- If the clock says "EDT", it is Daylight Time. If it says "EST", it is Standard Time.
- The offset number (UTC−4, UTC−5, etc.) is the absolute reference. A UTC−4 zone is always one hour ahead of a UTC−5 zone, regardless of what the local people call it.
Why some zones show Daylight Time and others Standard Time
All mainland zones change clocks on the same dates: second Sunday in March (spring forward) and first Sunday in November (fall back). So at any given moment, all mainland zones that observe DST are either all on Standard Time or all on Daylight Time.
Exceptions: - Arizona: Mountain Standard Time all year. No DST. - Hawaii: Hawaii-Aleutian Standard Time all year. No DST. - Alaska: Follows mainland DST schedule. - US territories: Puerto Rico, US Virgin Islands, Guam, American Samoa, Northern Mariana Islands all stay on Standard Time year-round. See US Territories Time Explained.
When the US time clocks refresh
The clocks tick in real time. The offset and abbreviation update automatically within a few seconds of the official DST change times (2:00 a.m. local on the changeover Sundays). No manual refresh is needed.
Scheduling across US zones with live time
When you need to schedule a call, meeting, or event across multiple US zones, use the live clocks to pick a window that works for everyone.
The safe window for the four mainland zones is 12:00 p.m. to 5:00 p.m. Eastern. That corresponds to: - 11:00 a.m., 4:00 p.m. Central - 10:00 a.m., 3:00 p.m. Mountain - 9:00 a.m., 2:00 p.m. Pacific
Adding Alaska shifts the window earlier: 12:00 p.m. Eastern = 8:00 a.m. Alaska. Adding Hawaii narrows it further: 12:00 p.m. Eastern = 6:00 a.m. Hawaii.
For full etiquette and strategies, see Calling Across US Time Zones: Best Times & Etiquette.
EDT or EST right now? How to check before you send the invite
"ET" is safe to use year-round. It means "the local time in the Eastern zone, whatever that happens to be today."
"EST" in July is wrong. "EDT" in December is wrong. If you write "EST" for a meeting in August, people on the West Coast will show up one hour early or late.
Always check the current abbreviation on the live clock before you send an invitation. See ET vs EST vs EDT: What's the Difference?.
US time zones at a glance: cities, offsets, DST rules
Keep this near your desk:
- Eastern: New York, Washington D.C., Boston, Atlanta, Miami. UTC−5 (winter) / UTC−4 (summer).
- Central: Chicago, Dallas, Houston, Nashville, New Orleans. UTC−6 (winter) / UTC−5 (summer).
- Mountain: Denver, Salt Lake City, Phoenix (no DST). UTC−7 (winter) / UTC−6 (summer, except Phoenix).
- Pacific: Los Angeles, San Francisco, Seattle, Portland. UTC−8 (winter) / UTC−7 (summer).
- Alaska: Anchorage. UTC−9 (winter) / UTC−8 (summer).
- Hawaii-Aleutian: Honolulu (no DST). UTC−10 year-round.
DST changes: second Sunday March (spring forward), first Sunday November (fall back).