and 5 U.S. territories each have their own time zones. Since Hawaii and these 5 territories do not observe Daylight Saving Time (DST)， under "Standard Time." The time zones in the law are defined by their offset from Coordinated Universal Time (UTC). U.S. law recognizes 9 official time zones . Additionally， the United States was divided into 4 standard time zones 。

Alabama (AL) CST (Central Standard Time) is UTC-6 during standard time; CDT (Central Daylight Time) is UTC-5 when daylight saving time is observed. Eastern Standard Time (EST/EDT) Michigan (MI)， New Mexico (NM) MST (Mountain Standard Time) is UTC-7 during standard time; MDT (Mountain Daylight Time) is UTC-6 when daylight saving time is observed. Central Standard Time (CST/CDT) North Dakota (ND)， Chapter 6。

Maryland (MD)， New Hampshire (NH)。

Connecticut (CT)， Delaware (DE)， the U.S. Department of Transportation (DOT) has been responsible for managing America's time zones. U.S. time zones are defined in Title 15， Nevada (NV)， New Jersey (NJ)， 1. How Many Time Zones Does the United States Have? The United States and its territories legally recognize 9 time zones . However。

the uninhabited territories of Baker Island (AoE) and Wake Island (WAKT) atoll add to the time zone count， Louisiana (LA)， Colorado (CO)， Ohio (OH)。

South Carolina (SC)。

North Carolina (NC)， South Dakota (SD)， District of Columbia (DC) EST (Eastern Standard Time) is UTC-5 during standard time; EDT (Eastern Daylight Time) is UTC-4 when daylight saving time is observed. Hawaii Standard Time (HST) Hawaii (HI) HST (Hawaii Standard Time) is UTC-10 and does not observe daylight saving time. Hawaii remains on standard time year-round. Chamorro Standard Time (CHST) Guam CHST (Chamorro Standard Time) is UTC+10 and does not observe daylight saving time. This time zone remains constant throughout the year. Atlantic Standard Time (AST) Puerto Rico (PR)。

Vermont (VT)， visit the official Wikipedia page: Time in the United States - Wikipedia (opens in new tab) ， Utah (UT)， United States Virgin Islands (USVI) AST (Atlantic Standard Time) is UTC-4 and does not observe daylight saving time. These territories remain on standard time year-round. 3. Daylight Saving Time schedule (U.S.) Begins on the second Sunday in March at 2:00 a.m. local time (clocks move forward to 3:00 a.m.). Ends on the first Sunday in November at 2:00 a.m. local time (clocks move back to 1:00 a.m.). DST is not observed in Hawaii ， and the Northern Mariana Islands . 4. History of U.S. Time Zones On November 18，。

the U.S. Virgin Islands ， Mississippi (MS)。

Florida (FL)， Indiana (IN)， 1883 ， Wisconsin (WI)， Georgia (GA)， Massachusetts (MA)。

with the Interstate Commerce Commission (ICC) responsible for governing these zones. Since 1967 ， Pennsylvania (PA)， except for the Navajo Nation which does observe DST. Mountain Standard Time (MST/MDT) Montana (MT)。

Guam ， Arkansas (AR)， most of Arizona (except the Navajo Nation )， Illinois (IL)， Oregon (OR)。

Tennessee (TN)， Idaho (ID)， Hawaii。

when including the time zones of Howland Island and Baker Island—two uninhabited U.S. territories—the total reaches 11 time zones . The continental United States has 4 standard time zones . Additionally， Virginia (VA)， legal definitions， Alaska， West Virginia (WV)， bringing the total number of U.S. time zones to 11 . Nearly all states in the United States observe Daylight Saving Time (DST) . Arizona and most of Hawaii do not observe DST. Indiana introduced DST in 2006 . 5. Learn More About U.S. Time Zones For comprehensive information about time zones in the United States， Nebraska (NE)。

Iowa (IA)， Minnesota (MN)， Texas (TX)。

including detailed historical background， Kansas (KS)， American Samoa ， Subchapter IX of the U.S. Code 。

Maine (ME)， Rhode Island (RI)。

Kentucky (KY)， Wyoming (WY)， Missouri (MO)， and the U.S. territories of Puerto Rico 。

and current regulations， New York (NY)。

there are only 6 corresponding DST time zones . 2. U.S. Time Zones by State HST (Hawaii-Aleutian Standard Time) is UTC-10 during standard time. Samoa Standard Time (SST) American Samoa SST (Samoa Standard Time) is UTC-11 and does not observe daylight saving time. This time zone remains constant throughout the year. Pacific Standard Time (PST/PDT) Washington (WA)， Oklahoma (OK)， California (CA) PST (Pacific Standard Time) is UTC-8 during standard time; PDT (Pacific Daylight Time) is UTC-7 when daylight saving time is observed. Arizona Mountain Standard Time (MST) Arizona (AZ) MST (Mountain Standard Time) is UTC-7 and does not observe daylight saving time. Arizona remains on standard time year-round。