MST stands for Mountain Time - Phoenix, Tucson, Mesa, Chandler and represents UTC-07:00. Note that MST is used by 2 different zones, so the correct offset depends on the location you mean.
Ambiguous Abbreviation
"MST" has 2 different meanings depending on the region.
UTC-07:00
Current time:
--:--:--UTC-06:00
Current time:
--:--:--