Understanding CST and MST
CST stands for Central Standard Time, UTC−6, used in Central North America. MST stands for Mountain Standard Time, UTC−7, used in Mountain North America. These are specific offset definitions, not automatic substitutes for the local time in a city.
How do you convert CST to MST?
Subtract the source offset from the destination offset: -420 − (-360) = -60 minutes. Subtract 60 minutes from the CST time. For example, 9:00 AM CST is 8:00 AM MST (same day). If the result crosses midnight, the calendar day changes too.
Does daylight saving time change this conversion?
The difference between these named offsets is fixed. A location may switch to a different abbreviation during daylight saving time, so an invitation saying “EST” can differ from the actual summer time in New York.
CST here means North American Central Standard Time, not China Standard Time (UTC+8) or Cuba Standard Time (UTC−5). Most US Central locations use CDT (UTC−5) in summer.
MST is UTC−7. Many Mountain locations use MDT (UTC−6) in summer; most of Arizona stays on MST.
Which day does the converted time fall on?
“Previous day” means the destination is one calendar day before the source; “Next day” means one day after. Dates are relative to the day of your input time. A time-only conversion cannot determine a specific calendar date.