The North American Central Time Zone is a time zone in parts of Canada, the United States, Mexico, Central America, some Caribbean islands, and part of the Eastern Pacific Ocean.
The Eastern Time Zone (ET) is a time zone encompassing part or all of 23 states in the eastern part of the United States, parts of eastern Canada, and the state of Quintana Roo in Mexico.
The Pacific Time Zone (PT) is a time zone encompassing parts of western Canada, the western United States, and western Mexico. Places in this zone observe standard time by subtracting eight hours from Coordinated Universal Time (UTC−08:00). During daylight saving time, a time offset of UTC−07:00 is used.
In the United States, time is divided into nine standard time zones covering the states, territories and other US possessions, with most of the country observing daylight saving time (DST) for approximately the spring, summer, and fall months. The time zone boundaries and DST observance are regulated by the Department of Transportation, but no single map of those existed until the agency announced intentions to make one in September 2022. Official and highly precise timekeeping services (clocks) are provided by two federal agencies: the National Institute of Standards and Technology (NIST) ; and the United States Naval Observatory (USNO). The clocks run by these services are kept synchronized with each other as well as with those of other international timekeeping organizations.
The Uniform Time Act of 1966, Pub. L. 89–387, 80 Stat. 107, enacted April 13, 1966, was a Law of the United States to "promote the adoption and observance of uniform time within the standard time zones" prescribed by the Standard Time Act of 1918. Its intended effect was to simplify the official pattern of where and when daylight saving time (DST) is applied within the U.S. Prior to this law, each state had its own scheme for when DST would begin and end, and in some cases, which parts of the state should use it.
UTC−07:00 is an identifier for a time offset from UTC of −07:00. In North America, it is observed in the Mountain Time Zone during standard time, and in the Pacific Time Zone during the other eight months. Some locations use it year-round.
UTC−06:00 is an identifier for a time offset from UTC of −06:00. In North America, it is observed in the Central Time Zone during standard time, and in the Mountain Time Zone during the other eight months. Several Latin American countries and a few other places use it year-round.
Canada is divided into six time zones. Most areas of the country's provinces and territories operate on standard time from the first Sunday in November to the second Sunday in March and daylight saving time the rest of the year.
The Chamorro Time Zone, formerly the Guam Time Zone, is a United States time zone which observes standard time ten hours ahead of Coordinated Universal Time (UTC+10:00). The clock time in this zone is based on the mean solar time of the 150th meridian east of the Greenwich Observatory.
Mexico uses four time zones:
Most of the United States observes daylight saving time, the practice of setting the clock forward by one hour when there is longer daylight during the day, so that evenings have more daylight and mornings have less. Exceptions include Arizona, Hawaii, and the overseas territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the United States Virgin Islands. The Uniform Time Act of 1966 established the system of uniform daylight saving time throughout the US.
The Mountain states form one of the nine geographic divisions of the United States that are officially recognized by the United States Census Bureau. It is a subregion of the Western United States.
In Canada, daylight saving time (DST) is observed in nine of the country's ten provinces and two of its three territories—though with exceptions in parts of several provinces and Nunavut.
Most of Mexico no longer observes daylight saving time as it was abolished on Sunday, 30 October 2022. The exceptions are the entire state of Baja California, as well as the border municipalities in Chihuahua, Coahuila, Nuevo León, and Tamaulipas which still observe daylight savings time matching the schedule of the United States beginning on the second Sunday of March and ending on the first Sunday of November.
Daylight saving time in the Americas is the arrangement in the Americas by which clocks are advanced by one hour in spring and moved back in autumn, to make the most of seasonal daylight. The practice is widespread in North America, with most of Canada and the United States participating, but much less so in Central and South America.
Almost all of Nevada is in the Pacific Time Zone. The few exceptions that exist all observe Mountain Time and are close to the borders of Idaho or Utah. Other than these minor exceptions, Nevada is the only non coastal state to be entirely on Pacific Time, most of Idaho uses Mountain Time, and Arizona is officially on Mountain Time except for the 2/3 of the year when Daylight Saving Time is in effect, which they don't observe.
Alaska is officially covered by two time zones - the Alaska Time Zone and the Hawaii-Aleutian Time Zone. The Hawaii-Aleutian Time Zone is used for the Aleutian Islands west of 169°30′W, and the rest of the state uses the Alaska Time Zone. The entirety of Alaska observes daylight saving time.
Time in Arizona, as in all U.S. states, is regulated by the United States Department of Transportation as well as by state and tribal law.
The U.S. state of Idaho is covered by two time zones, as described below. All locations observe daylight saving time.
