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|Central Time Zone (North America)|
|23:21, 4 December 2019 CST|
|Observance of DST|
|DST is observed in some of this time zone.|
The North American Central Time Zone (CT) is a time zone in parts of Canada, the United States, Mexico, Central America, some Caribbean Islands, and part of the Eastern Pacific Ocean.
Central Standard Time (CST) is six hours behind Coordinated Universal Time (UTC). During summer most of the zone uses daylight saving time (DST), and changes to Central Daylight Time (CDT) which is five hours behind UTC.
The largest city in the Central Time Zone is Mexico City; the Mexico City metropolitan area is the largest metropolitan area in the zone and North America.
The province of Manitoba is the only province or territory in Canada that observes Central Time in all areas.
The following Canadian provinces and territories observe Central Time in the areas noted, while their other areas observe Eastern Time:
Also, most of the province of Saskatchewan is on Central Standard Time year-round, never adjusting for Daylight Saving Time. Major exceptions include Lloydminster, a city situated on the boundary between Alberta and Saskatchewan. The city charter stipulates that it shall observe Mountain Time and DST, putting the community on the same time as all of Alberta, including the major cities of Calgary and Edmonton. As a result, during the summer, clocks in the entire province match those in Alberta, but during the winter, clocks in most of the province match those in Manitoba.
Ten states are contained entirely in the Central Time Zone:
Five states are split between the Central Time Zone and the Mountain Time Zone:
Five states are split between the Central Time Zone and the Eastern Time Zone:
Most of Mexico—roughly the eastern three-fourths—lies in the Central Time Zone, except for six northwestern states (Baja California, Baja California Sur, Chihuahua, Sinaloa, Sonora, and *most of Nayarit) and one southeastern state (Quintana Roo).
The federal entities of Mexico that observe Central Time:
Belize, Costa Rica, El Salvador, Guatemala, Honduras, and Nicaragua all use Central Standard Time year-round.
The Galápagos Islands in Ecuador uses Central Standard Time all year-round; the remainder of Ecuador uses Eastern Standard Time. Both Easter Island and Salas y Gómez Island in Chile uses Central Standard Time during the Southern Hemisphere winter and Central Daylight Time during the Southern Hemisphere summer; the remainder of Chile uses Atlantic Standard Time and Atlantic Daylight Time.
Daylight saving time (DST) is in effect in much of the Central time zone between mid-March and early November. The modified time is called "Central Daylight Time" (CDT) and is UTC−05:00. In Canada, Saskatchewan does not observe a time change. One reason for Saskatchewan's lack of a time change is that, geographically, the entire province is closer to the Mountain Time Zone's meridian. The province elected to move onto "permanent" daylight saving by being part of the Central Time Zone. The only exception is the region immediately surrounding the Saskatchewan side of the biprovincial city of Lloydminster, which has chosen to use Mountain Time with DST, synchronizing its clocks with those of Alberta.
In those areas of the Canadian and American time zones that observe DST, beginning in 2007, the local time changes at 02:00 local standard time to 03:00 local daylight time on the second Sunday in March and returns at 02:00 local daylight time to 01:00 local standard time on the first Sunday in November. Mexico decided not to go along with this change and observes their horario de verano from the first Sunday in April to the last Sunday in October. In December 2009, the Mexican Congress allowed ten border cities, eight of which are in states that observe Central Time, to adopt the U.S. daylight time schedule effective in 2010.
Lloydminster is a Canadian city which has the unusual geographic distinction of straddling the provincial border between Alberta and Saskatchewan. The city is incorporated by both provinces as a single city with a single municipal administration.
The Eastern Time Zone (ET) is a time zone encompassing part or all of 22 states in the eastern part of the contiguous United States, parts of eastern Canada, the state of Quintana Roo in Mexico, Panama in Central America, and certain Caribbean and Atlantic islands, along with certain countries and parts of countries in South America. Places that use Eastern Standard Time (EST) when observing standard time (autumn/winter) are five hours behind Coordinated Universal Time (UTC−05:00).
The Mountain Time Zone of North America keeps time by subtracting seven hours from Coordinated Universal Time (UTC) when standard time is in effect, and by subtracting six hours during daylight saving time (UTC−06:00). The clock time in this zone is based on the mean solar time at the 105th meridian west of the Greenwich Observatory. In the United States, the exact specification for the location of time zones and the dividing lines between zones is set forth in the Code of Federal Regulations at 49 CFR 71.
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.
Time in the United States, by law, is divided into nine standard time zones covering the states, territories and other US possessions, with most of the United States 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. 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.
UTC−05:00 is an identifier for a time offset from UTC of −05:00. In North America, it is observed in the Eastern Time Zone during standard time, and in the Central Time Zone during the other eight months. The western Caribbean uses it year round.
The Atlantic Time Zone is a geographical region that keeps standard time—called Atlantic Standard Time (AST)—by subtracting four hours from Coordinated Universal Time (UTC), resulting in UTC−04:00. During part of the year, some portions of the zone observe daylight saving time, referred to as Atlantic Daylight Time (ADT), by moving their clocks forward one hour to result in UTC−03:00. The clock time in this zone is based on the mean solar time of the 60th meridian west of the Greenwich Observatory.
UTC−04:00 is an identifier for a time offset from UTC of −04:00. It is observed in the Eastern Time Zone during the warm months of daylight saving time, as Eastern Daylight Time. The Atlantic Time Zone observes it during standard time . It is observed all year in the Eastern Caribbean.
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 8 months. A few places 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.
Australia uses three main time zones: Australian Western Standard Time, Australian Central Standard Time, and Australian Eastern Standard Time. Time is regulated by the individual state governments, some of which observe daylight saving time (DST). Australia's external territories observe different time zones.
Time in Brazil is calculated using [standard time], and the country is divided into four standard time zones: UTC−02:00, UTC−03:00, UTC−04:00 and UTC−05:00.
Canada is divided into six time zones, based on proposals by Scottish Canadian railway engineer Sir Sandford Fleming, who pioneered the use of the 24-hour clock, the world's time zone system, and a standard prime meridian. Most of Canada operates 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 Canadian province of Saskatchewan is geographically located in the Mountain Time Zone. However, most of the province observes Central Standard Time year-round. As a result, it is effectively on daylight saving time (DST) year round, as clocks are not turned back an hour in autumn when most jurisdictions return to standard time.
Mexico uses four main time zones since February 2015. Most of the country observes Daylight Saving Time.
Daylight saving time in the United States is the practice of setting the clock forward by one hour during the warmer part of the year, so that evenings have more daylight and mornings have less. Most areas of the United States and Canada observe daylight saving time (DST), the exceptions being 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.
Nunavut is divided into three time zones: Eastern, Central and Mountain.
Daylight saving time (DST) is observed in all ten Canadian provinces and three territories. However, there are exceptions: most of Saskatchewan observes Central Standard Time year-round and most of the territory of Nunavut, with its three time zones, observes daylight saving time. Under the Canadian Constitution, laws related to timekeeping are a provincial or territorial matter.
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, Mexico, and the United States of America participating, but much less so in South America.
Time zones in North America
|Time zone||Hours from UTC: Standard time||Hours from UTC: Daylight saving time|
|Hawaii–Aleutian (in Hawaii)||–10||–10|
|Hawaii–Aleutian (in Alaska)||–10||–9|
|Pacific (in Alaska)||–8||–8|
|Pacific (other states/provinces)||–8||–7|
|Mountain (Arizona, Sonora, and Northeastern British Columbia only)||–7||–7|
|Mountain (other states/provinces)||–7||–6|
|Central (Saskatchewan only)||–6||–6|
|Central (other states/provinces)||–6||–5|
|Eastern (parts of Nunavut and the Caribbean)||–5||–5|
|Eastern (other states/provinces)||–5||–4|
|Atlantic (Natashquan River)||–4||–4|
|Atlantic (other states/provinces)||–4||–3|
| Saint Pierre and Miquelon |
and most of Greenland