US Time Zone Map

How many time zones are there on the map of the United States?

The main area of the country covers six time zones, made up of the four areas of the contiguous states of continental North America, plus the state of Alaska and the Hawaiian Islands. However, the United States governs a total of nine time zones including the unincorporated territories: Puerto Rico, the Virgin Islands, American Samoa, Guam, and the Mariana Islands. 

How is the United States time zone calculated?

Time zones are calculated by compensation, adding or subtracting hours from Coordinated Universal Time (UTC); the UTC baseline is plotted along the prime meridian. The territories to the west of the Greenwich Meridian subtract hours from the clock, while those located to the east add hours. Time zones are generally expressed as UTC (or also GMT), followed by the + or – sign and the number of hours, depending on the zone. 

On the time map of the United States, the only area that is located on the eastern side in relation to UTC is the Chamorro time zone (UTC+10). All other time zones are calculated by subtracting hours from the clock as they move away to the west. So, when it’s noon in London (UK), it’s 7:00 in the morning in New York and 4:00 a.m. in Los Angeles.

What time zones are there in the United States?

From east to west, the time zones that comprise the areas the United States governs are as follows:

• In UTC+10: Chamorro Standard Time, abbreviated ChST. On the map of the United States, this area reaches the island of Guam and the Northern Mariana Islands, which share a time zone with Australian Eastern Standard Time, Papua New Guinea, and Vladivostok Time in Russia. 
• In UTC-4: Atlantic Standard Time (AST), including Puerto Rico and the Virgin Islands. This is the same time zone as Quebec (Canada), many Caribbean Islands (including Cuba and the Dominican Republic), Venezuela, part of Brazil, Bolivia, Paraguay, and Chile.
• In UTC-5: Eastern Standard Time (EST). It covers 23 states in continental North America that are along the Atlantic Coast and the Ohio Valley. It is one of the four zones of the so-called contiguous states in the United States. New York and Washington D. C. are two of the cities that are usually used as references for EST. It is partially shared with countries such as Canada, Mexico, Peru, and Brazil.
• In UTC-6: Central Standard Time (CST). It runs roughly from the Gulf Coast to the Mississippi Valley and the Great Plains. Dallas and Chicago are usually two of the reference points when talking about this time zone. CST is one of the four zones of the contiguous states in the United States. It shares the same time zone as Canada, Mexico, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, and the Galapagos Islands (Ecuador). 
• In UTC-7: the Mountain Standard Time (MST). This is another of the four areas in the contiguous United States. It covers Arizona, Montana, New Mexico, Colorado, Utah, and Wyoming, as well as parts of Idaho, Kansas, Nebraska, Nevada, North Dakota, Oklahoma, South Dakota, Oregon, and Texas. Denver, the capital of Colorado, is a city that’s often used to reference this time zone.
• In UTC-8: Pacific Standard Time (PST). It covers the western region of the country: California, Washington, part of Nevada, Oregon, and Idaho. This time zone also covers part of Mexico and Canada. It belongs to one of the four time zones in the contiguous United States. The reference city for PST is usually Los Angeles.
• In UTC-9: Alaska Standard Time (ALKS). This time zone is shared with the Gambier Islands of French Polynesia.
• In UTC-10: Hawaiian-Aleutian Standard Time (HAST), also known as Hawaii Standard Time (HST). 
• In UTC-11: Samoa Standard Time (SST). It covers American Samoa, the westernmost point of the United States’ territory. This time zone is shared with New Zealand.