Highlighted rows fall within 09:00–18:00 in both places: 5 shared working hours.
How many hours is CST ahead of HAST?
As abbreviations, HAST is always 4 hours behind of CST: CST is UTC−6 and HAST is UTC−10. To convert, subtract 4 hours.
When the CST to HAST time difference changes
For most of the year HAST is 5 hours behind of CST. From 1 November to 31 December 2026, HAST is 4 hours behind of CST instead, because the two places change their clocks on different dates. Meetings booked by the usual gap land an hour off in those weeks.
Dates
HAST vs CST
Length
1 November 2026 to 31 December 2026
4 hours behind
61 days
1 January 2027 to 13 March 2027
4 hours behind
72 days
14 March 2027 to 6 November 2027
5 hours behind
238 days
7 November 2027 to 31 December 2027
4 hours behind
55 days
When CST and HAST are both at work
When HAST is 5 hours behind of CST: 3 shared office hours, 14:00 to 17:00 in CST (09:00 to 12:00 in HAST).
When HAST is 4 hours behind of CST: 4 shared office hours, 13:00 to 17:00 in CST (09:00 to 13:00 in HAST).
Frequently asked questions about CST and HAST time
How many hours ahead is HAST of CST?
HAST (UTC−10) is 4 hours behind of CST (UTC−6).
Does the time difference between CST and HAST change?
Yes. It is usually 5 hours behind, but changes when one side moves its clocks: 4 hours behind from 1 November to 31 December 2026; 4 hours behind from 1 January to 13 March 2027.