(August 2014). The 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.Time in the zone is six hours behind Coordinated Universal Time (Greenwich Mean Time-GMT).During daylight saving time (DST), time in most (but not all) of the zone is five hours behind GMT.aylight 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−5. In Canada, Saskatchewan does not observe a time change.