The Central Time Zone is in North America and observes standard time by subtracting six hours from Coordinated Universal Time during standard time (UTC−06) and five hours during daylight saving time (UTC−05). The clock time in this zone, composed almost totally of a strip of territory in North America, is based on the mean solar time of the 90th meridian west of the Greenwich Observatory.
In the United States and Canada, this time zone is generically called Central Time (CT), while in Mexico is called Tiempo del Centro. Specifically, it is Central Standard Time (CST) when observing standard time (winter), and Central Daylight Time (CDT) when observing daylight saving (summer). In Mexico, daylight saving time is known as Horario de Verano ("Summer Time"), no matter what time zone.