CST (Central Standard Time, UTC−6) and CDT (Central Daylight Time, UTC−5) cover the Central Time Zone of North America. This zone includes Chicago, Dallas, Houston, Minneapolis, and Kansas City — some of the US's largest cities. Like other US zones, Central Time shifts by one hour twice a year with daylight saving time.
The Confusing CST Overlap
'CST' is one of the most ambiguous time zone abbreviations in the world. It can mean Central Standard Time (UTC−6, North America), China Standard Time (UTC+8), or Cuba Standard Time (UTC−5). When writing to an international audience, always pair CST with its UTC offset or use the IANA zone name (America/Chicago, Asia/Shanghai, America/Havana).
Parts of Central Time That Don't Observe CDT
Most of Mexico's northern states — including parts of Chihuahua, Sonora, and others — historically observed Central Time, but Mexico largely eliminated DST in 2023. The state of Sonora permanently observes Mountain Standard Time (UTC−7) year-round to align with Arizona. Saskatchewan in Canada observes Central Standard Time (UTC−6) permanently, without any DST change.
Some states have counties in different time zones — parts of Indiana, Kentucky, and Tennessee observe Central Time while the rest of the state observes Eastern Time.
