Central Time Zone

The North American Central Time Zone (CT) is a time zone in parts of Canada, the United States, Mexico, Central America, and a few Caribbean islands.
In parts of that zone (20 states in the US, three provinces or territories in Canada, and several border municipalities in Mexico), the Central Time Zone is affected by two time designations yearly: Central Standard Time (CST) is observed from the first Sunday in November to the second Sunday in March. It is six hours behind Coordinated Universal Time (UTC) and designated internationally as UTC−6. From the second Sunday in March to the first Sunday in November the same areas observe daylight saving time (DST), creating the designation of Central Daylight Time (CDT), which is five hours behind UTC and known internationally as UTC−5.
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. One major exception includes Lloydminster, a city whose borders overlap both 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 (UTC−7) in the winter, and in time with Saskatchewan (UTC−6) during the summer.
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:
Additionally, Phenix City, Alabama, and several nearby communities in Russell County, Alabama, unofficially observe Eastern Time. This is due to their close proximity to Columbus, Georgia, which is on Eastern Time.
Although legally located within the Central Time Zone, Kenton, Oklahoma—located to the adjacent east of the defined border of the Central and Mountain time zones (at the Oklahoma−New Mexico state line)—unofficially observes Mountain Time. This is reportedly because most people who interact with the town reside in either New Mexico or Colorado.
Most of Mexico—roughly the eastern three-fourths—lies in the Central Time Zone, except for five northwestern states (Baja California, Baja California Sur, Sinaloa, Sonora, and most of Nayarit) and one southeastern state (Quintana Roo). It is known locally as the Zona Centro.
The federal entities of Mexico that observe Central Time:
Out of the seven countries comprising Central America, all but one use Central Standard Time year-round:
Panama, which recognizes Eastern Standard Time (UTC−5) year round, is the exception.
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 the United States, all time zones that observe DST were effectively changed by the Energy Policy Act of 2005. Beginning in 2007, DST would now begin at 2 a.m. (02:00) on the second Sunday in March instead of the first Sunday in April, moving the time from 2 to 3 a.m. (i.e., from 02:00 to 03:00). Additionally, DST would end at 2 a.m. (02:00) on the first Sunday in November instead of the last Sunday in October, moving the time from 2 to 1 a.m. (i.e., from 02:00 to 01:00).
At the time, Mexico decided not to go along with this change and observed their horario de verano ("summer schedule") 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 US daylight time schedule effective in 2010. In October 2022, however, CDT was used in Mexico for the last time after DST was abolished. The US is also seeing traction in the same direction, with the Sunshine Protection Act that proposes legislation that would permanently end the switching of times and make daylight saving time permanent.