Central Time Zone (North America)
The Central Time Zone observes standard time by subtracting six hours from UTC during standard time (UTC−6) and five hours during daylight saving time (UTC−5). The clock time in this zone is based on the mean solar time of the 90th degree meridian west of the Greenwich Observatory.
In the United States and Canada, this time zone is generically called Central Time (CT). Specifically, it is Central Standard Time (CST) when observing standard time (Winter), and Central Daylight Time (CDT) when observing daylight saving (Summer).
The zone is one hour ahead of the Mountain Time Zone and one hour behind the Eastern Time Zone.
In Canada, this time zone includes all of Manitoba, nearly all of Saskatchewan, a slice of Northwestern Ontario, and part of Nunavut (most of Kivalliq Region and part of Qikiqtaaluk Region).
In the United States, the time zone includes the entire area of the states of Alabama, Arkansas, Illinois, Iowa, Louisiana, Minnesota, Missouri, Mississippi, Oklahoma, and Wisconsin; and portions of Florida, Indiana, Kansas, Kentucky, Michigan, Nebraska, North Dakota, South Dakota, Tennessee, and Texas. The exact specification for the location of time zones and the dividing line between zones is set forth in the Code of Federal Regulations at 49 CFR 71.[1]
Most of Mexico belongs to the Central Time Zone, with the six northwestern-most states being the exception.
UTC−6 is also observed in the Central American countries of Belize, Guatemala, Honduras, El Salvador, Nicaragua and Costa Rica. In South America, this zone includes the Ecuadorian province of Galápagos. In Oceania, the Chilean Easter Island also belongs to this time zone.
Central Daylight Time
Daylight Saving Time is in effect in much of the time zone between mid-March and early November. The modified time is called Central Daylight Time (CDT) and is UTC−5. Saskatchewan, Central America and Galápagos do not observe the change, remaining on Standard Time year round. One reason that Saskatchewan does not take part in the time change is that geographically, most of the province should be placed in the Mountain Time Zone. To avoid this, they have moved 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 some areas, starting in 2007, the local time changes from CST to CDT at 02:00 LST to 03:00 LDT on the second Sunday in March and returns at 02:00 LDT to 01:00 LST on the first Sunday in November.
Broadcasting concerns
Due to the structure of broadcasting networks in the United States (mostly television, but to a lesser extent radio as well), programming is aired simultaneously in the Eastern and Central Time zones, which accounts for lines such as "tonight at 8/7 Central" on many network promotional ads. As a result, morning programming lineups designed for East Coast viewers may start too early for viewers in the Midwest and the central South; hence, they are tape-delayed to air at 7:00 am Central (except when breaking news happens or special occasions such as the Macy's Thanksgiving Day Parade, which airs at 9:00 am Eastern/8:00 am Central, pushing back the morning shows to air live at 6:00 am Central).
Also, an hour of syndicated programming time (between 7:00 pm and 8:00 pm in the Eastern Time Zone) is lost since network prime time starts at 7:00 pm Central, forcing TV stations to choose from airing their 6:00 pm newscast and a program, or airing shows in 'blocks' preferred by syndicators (i.e. Wheel of Fortune and Jeopardy! together, or Entertainment Tonight and The Insider). Many stations in the Central Time Zone tend to air one or both parts of the syndicated block at 5:00 pm or even earlier. The most common set of programming chosen by the big three television networks (ABC, CBS, and NBC) is to air a newscast at 5:00 pm, national news at 5:30 pm, local news at 6:00 pm, and syndicated programming at 6:30 pm. Some stations even show a newscast from 6:00 to 7:00 pm. Another more recent dilemma of the 7:00 pm prime time start is that a combination of longer commutes and work hours than in the past have caused many people to not come home from work until after 7:00 pm, cutting into the potential ratings of shows that start at this time.
Similarly, media coverage of New Year's Eve celebrations in New York City often leave the Central Time Zone out. Late Night with Conan O'Brien, though produced in New York, when broadcast on New Year's Eve (as it does not air on weekends) takes advantage of its later time slot (11:35 pm Central) to lampoon this inconsistency and produce its own New Year's countdown for television viewers in the Central Time Zone, although most viewers are often sent to local network affiliates for regional New Year's Eve celebrations.
Interestingly, US broadcast networks do tape delay in the other two continental US time zones. The Mountain Time Zone is tape-delayed one hour and the Pacific Time Zone three hours from original broadcasts, so that shows match the broadcast times of the Central and Eastern Time Zones respectively (e.g. prime time begins at 7:00 pm MT and 8:00 pm PT) except during sporting events and other selected live events.
Canadian broadcasting networks, with 5 1/2 time zones to span and a larger percentage of its audience residing in the Mountain Time Zone than in the Central Time Zone (which only has one significant metropolitan area - Winnipeg, Manitoba), sometimes are able to avoid these issues by airing prerecorded programs on local time (except Newfoundland time), although adjustments are often still made, particularly on private networks (mainly due to the influence of U.S. television). This is particularly a problem in Saskatchewan as Central Standard Time is used year round, choosing not to change to Daylight Saving Time during the summer. While Saskatchewan, Manitoba and parts of northwestern Ontario share the same clock setting during the winter season, Saskatchewan and Alberta share the same clock setting during the summer season, despite the fact that Alberta is in the Mountain Time Zone. Schedules must be adjusted for the summer season.
The problem is largely moot in Mexico and other parts of Latin America because of the lack of significant other time zones.
Alphabetical list of cities and metropolitan areas
- Acapulco, Guerrero
- Appleton, Wisconsin
- Austin, Texas
- Aguascalientes, Aguascalientes
- Baton Rouge, Louisiana
- Belize City, Belize
- Bismarck, North Dakota
- Birmingham, Alabama
- Bowling Green, Kentucky
- Carbondale, Illinois
- Cedar Rapids, Iowa
- Chicago, Illinois
- Columbia, Missouri
- Corpus Christi, Texas
- Cuernavaca, Morelos
- Dallas-Ft. Worth, Texas
- Des Moines, Iowa
- Duluth, Minnesota
- Evansville, Indiana
- Fargo, North Dakota
- Gary, Indiana
- Grand Forks, North Dakota
- Guadalajara, Jalisco
- Guatemala City
- Green Bay, Wisconsin
- Houma-Bayou-Cane-Thibodaux, Louisiana
- Houston, Texas
- Huntsville, Alabama
- Jackson, Mississippi
- Kansas City, Missouri-Kansas
- Kenosha, Wisconsin
- La Crosse, Wisconsin
- León, Guanajuato
- Lincoln, Nebraska
- Little Rock, Arkansas
- Madison, Wisconsin
- Managua
- Memphis, Tennessee
- Mérida, Yucatán
- Mexico City
- Milwaukee, Wisconsin
- Minneapolis-St. Paul, Minnesota
- Mobile, Alabama
- Monterrey, Nuevo León, Mexico
- Montgomery, Alabama
- Nashville, Tennessee
- New Orleans, Louisiana
- Norman, Oklahoma
- Oklahoma City, Oklahoma
- Omaha, Nebraska
- Panama City, Florida
- Pensacola, Florida
- Puebla, Puebla
- Quad Cities, Iowa and Illinois
- Regina, Saskatchewan
- Rockford, Illinois
- St. Louis, Missouri
- San Antonio, Texas
- San José, Costa Rica
- San Luis Potosí, San Luis Potosí
- San Salvador, El Salvador
- Santiago de Querétaro, Querétaro
- Saskatoon, Saskatchewan
- Shreveport, Louisiana
- Sioux Falls, South Dakota
- Tampico, Tamaulipas
- Tegucigalpa, Honduras
- Toluca, México
- Torreón, Coahuila
- Tulsa, Oklahoma
- Wichita, Kansas
- Winnipeg, Manitoba
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---|---|---|---|---|---|---|---|---|---|---|
Time Zone | UTC-10 | UTC-9 | UTC-8 | UTC-7 | UTC-6 | UTC-5 | UTC-4 | UTC-3:30 | UTC-3 | UTC-2:30 |
Name | Hawaii-Aleutian Standard | Alaska Standard
Hawaii-Aleutian Daylight |
Pacific Standard
Alaska Daylight |
Mountain Standard
Pacific Daylight |
Central Standard
Mountain Daylight |
Eastern Standard
Central Daylight |
Atlantic Standard
Eastern Daylight |
Newfoundland Standard | Atlantic Daylight | Newfoundland Daylight |
References
- ^ The specification for the Central Time Zone is set forth at 49 CFR 71.6, and is listed in Text and pdf formats.
The boundary between Eastern and Central is set forth at 49 CFR 71.5, and is listed in text and pdf formats.The boundary between Central and Mountain is set forth at 49 CFR 71.7, and is listed in text and pdf formats.