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US Time Zones

The 50 states use six time zones: Eastern, Central, Mountain, Pacific, Alaska and Hawaii-Aleutian. Arizona and Hawaii stay on standard time all year, which is why Arizona gets its own clock below.

Offsets and abbreviations

ZoneWinterSummerIANA name
Eastern TimeUTC−05:00UTC−04:00America/New_York
Central TimeUTC−06:00UTC−05:00America/Chicago
Mountain TimeUTC−07:00UTC−06:00America/Denver
Arizona (Mountain Standard)UTC−07:00no changeAmerica/Phoenix
Pacific TimeUTC−08:00UTC−07:00America/Los_Angeles
Alaska TimeUTC−09:00UTC−08:00America/Anchorage
Hawaii-Aleutian TimeUTC−10:00no changePacific/Honolulu

The usual abbreviations are EST/EDT, CST/CDT, MST/MDT, PST/PDT, AKST/AKDT and HST. The first letter names the zone, and S or D says whether it is standard or daylight time. The Aleutian Islands west of 169°30′W use Hawaii-Aleutian Time but, unlike Hawaii, change their clocks (America/Adak).

US territories use three more zones, none with daylight saving time: Atlantic Time (UTC−4) in Puerto Rico and the US Virgin Islands, Samoa Time (UTC−11) in American Samoa, and Chamorro Time (UTC+10) in Guam and the Northern Mariana Islands.

Daylight saving time

Daylight saving time begins at 2:00 a.m. local time on the second Sunday in March and ends at 2:00 a.m. local time on the first Sunday in November. A state may keep standard time all year, as Arizona and Hawaii do, but federal law does not allow permanent daylight time. Upcoming changes on the East Coast:

Time zone by state

Where a state uses two zones, the one covering most people is listed first. States with a full guide are linked.

StateTime zoneNotes
AlabamaCentral Time
AlaskaAlaska Time / Hawaii-Aleutian TimeAleutian Islands west of 169°30′W use Hawaii-Aleutian Time.
ArizonaArizona (no DST)No daylight saving time, except on the Navajo Nation.
ArkansasCentral Time
CaliforniaPacific Time
ColoradoMountain Time
ConnecticutEastern Time
DelawareEastern Time
District of ColumbiaEastern Time
FloridaEastern Time / Central TimeWestern Panhandle is on Central Time.
GeorgiaEastern Time
HawaiiHawaii-Aleutian TimeNo daylight saving time.
IdahoMountain Time / Pacific TimeNorthern Idaho is on Pacific Time.
IllinoisCentral Time
IndianaEastern Time / Central TimeCounties in the northwest and southwest corners are on Central Time.
IowaCentral Time
KansasCentral Time / Mountain TimeGreeley, Hamilton, Sherman and Wallace counties are on Mountain Time.
KentuckyEastern Time / Central TimeWestern Kentucky is on Central Time.
LouisianaCentral Time
MaineEastern Time
MarylandEastern Time
MassachusettsEastern Time
MichiganEastern Time / Central TimeFour Upper Peninsula counties on the Wisconsin border are on Central Time.
MinnesotaCentral Time
MississippiCentral Time
MissouriCentral Time
MontanaMountain Time
NebraskaCentral Time / Mountain TimeThe western third is on Mountain Time.
NevadaPacific Time / Mountain TimeWest Wendover is on Mountain Time.
New HampshireEastern Time
New JerseyEastern Time
New MexicoMountain Time
New YorkEastern Time
North CarolinaEastern Time
North DakotaCentral Time / Mountain TimeThe southwest corner is on Mountain Time.
OhioEastern Time
OklahomaCentral Time
OregonPacific Time / Mountain TimeMost of Malheur County, on the Idaho border, is on Mountain Time.
PennsylvaniaEastern Time
Rhode IslandEastern Time
South CarolinaEastern Time
South DakotaCentral Time / Mountain TimeThe western half is on Mountain Time.
TennesseeCentral Time / Eastern TimeEast Tennessee is on Eastern Time.
TexasCentral Time / Mountain TimeEl Paso and Hudspeth counties are on Mountain Time.
UtahMountain Time
VermontEastern Time
VirginiaEastern Time
WashingtonPacific Time
West VirginiaEastern Time
WisconsinCentral Time
WyomingMountain Time

Who sets the time zones

Congress created the zones, and the US Department of Transportation draws and moves the boundaries between them. The current lines are written out county by county in 49 CFR Part 71. A county that wants to change zones petitions the Department of Transportation, which is why the lines move from time to time.

Not sure which zone you are in right now? Check your device's time zone.

Sources