Area code time zones
Every area code on this site belongs to one time zone for its region: Eastern, Central, Mountain, or Pacific, with one clear exception in Arizona. The time zone on a code page is the zone for that code’s region, not necessarily for its whole state.
The four zones, in order
Eastern Time is the furthest east, followed by Central Time one hour behind Eastern, Mountain Time one hour behind Central, and Pacific Time one hour behind Mountain. A call placed at noon Eastern Time therefore reaches a Central Time region at 11 in the morning, a Mountain Time region at 10, and a Pacific Time region at 9, before any daylight saving adjustment. The Batch 1 Eastern examples include 212 in Manhattan, 404 in inner Atlanta, and 617 in the Boston area. The Central examples include 214 in the Dallas area, 312 in downtown Chicago, and 615 in Nashville and Middle Tennessee. The Pacific examples include 206 in the Seattle area, 213 in central Los Angeles, and 702 in Clark County and Las Vegas.
Daylight saving time, in general terms
Most US time zones shift by one hour during daylight saving time, moving to a daylight variant in summer and back to standard time in winter. That means the clock difference between two regions can stay the same in hours, because both regions shift together, but the actual clock time in each region still moves. Callers should check the current local time for the region, not assume a fixed clock reading from a code alone. This guide gives no daylight saving dates, because they can change; the code page gives the zone, and a current clock check gives the time.
The Arizona exception
Arizona is the exception that causes the most confusion. 602 covers the Phoenix area and stays on Mountain Standard Time all year, because Arizona does not observe daylight saving time. By contrast, 720 covers the Denver-Boulder area in Colorado and follows Mountain Time with daylight saving, moving between Mountain Standard Time in winter and Mountain Daylight Time in summer. In winter, Phoenix and Denver show the same clock time, but in summer Denver moves one hour ahead of Phoenix. Any guide that calls both codes simply ‘Mountain Time’ without that note will mislead a summer caller, so this site states the Arizona rule on the 602 page and on this guide.
Split states
Some states span more than one time zone, so a state name alone does not settle the time for a call. Texas, for example, is split between Central and Mountain time, but the 214 Dallas region is Central only. Florida is split between Eastern and Central time, but the 305 Miami-Dade and Keys region is Eastern only. Tennessee is split between Central and Eastern time, but the 615 Nashville region is Central only. Michigan is split between Eastern and Central time, but the 616 Grand Rapids region is Eastern only. The rule is simple: trust the time zone on the individual code page, and use the state only as a starting point.
Frequently asked questions
If two codes are in the same state, are they in the same time zone?
Not always. Split states have more than one zone, so check the zone on each code page rather than assuming it from the state.
Why is Arizona different from Colorado in summer?
Because Arizona does not observe daylight saving time, while Colorado does. Phoenix stays on Mountain Standard Time, while Denver moves to Mountain Daylight Time in summer.
Does an area code itself set the time?
No. The code identifies a region, and that region has a time zone. The code page gives the zone, and the current date decides whether daylight saving applies in that zone.
What time should I call across zones?
Check the current local time in the code’s region first, and aim for daytime hours there.
Sources: NANPA Area Code Search tool; NANPA planning letters cited on the Batch 1 code pages.
Based on a recent search of NANPA and official sources.
This website provides general information about North American area codes, compiled from public sources including NANPA. It is not affiliated with or endorsed by the FCC, NANPA or any telephone carrier. Area code details can change; confirm with your carrier or the official NANPA website. This site does not identify callers or phone owners.