What is AST in CST?
Central Time is 2 hours behind
Atlantic Time is on UTC−3:00 and Central Time is on UTC−5:00 right now. Both are on daylight saving, so their clocks read ADT and CDT. That gap holds all year, because both zones change their clocks together.
- Time in Halifax
- 11:13 pm
- Time in Chicago
- 9:13 pm
- Difference
- −2 h
- Next clock change
- November 1, 2026
Convert a time
CDT — Central Time
9:00 pm
Tue
Daylight saving
Atlantic Time
Clocks go back one hour at 2am local time, becoming AST.
Central Time
Clocks go back one hour at 2am local time, becoming CST.
AST to CST conversion table
Every hour of Tuesday, September 22, 2026, converted from Atlantic Time to Central Time. 2 of the 24 hours fall on a different calendar day in Chicago, which is marked.
- 12:00 am ADT
- 10:00 pm CDT−1 day
- 1:00 am ADT
- 11:00 pm CDT−1 day
- 2:00 am ADT
- 12:00 am CDT
- 3:00 am ADT
- 1:00 am CDT
- 4:00 am ADT
- 2:00 am CDT
- 5:00 am ADT
- 3:00 am CDT
- 6:00 am ADT
- 4:00 am CDT
- 7:00 am ADT
- 5:00 am CDT
- 8:00 am ADT
- 6:00 am CDT
- 9:00 am ADT
- 7:00 am CDT
- 10:00 am ADT
- 8:00 am CDT
- 11:00 am ADT
- 9:00 am CDT
- 12:00 pm ADT
- 10:00 am CDT
- 1:00 pm ADT
- 11:00 am CDT
- 2:00 pm ADT
- 12:00 pm CDT
- 3:00 pm ADT
- 1:00 pm CDT
- 4:00 pm ADT
- 2:00 pm CDT
- 5:00 pm ADT
- 3:00 pm CDT
- 6:00 pm ADT
- 4:00 pm CDT
- 7:00 pm ADT
- 5:00 pm CDT
- 8:00 pm ADT
- 6:00 pm CDT
- 9:00 pm ADT
- 7:00 pm CDT
- 10:00 pm ADT
- 8:00 pm CDT
- 11:00 pm ADT
- 9:00 pm CDT
Scheduling between the two
Working hours overlap from 11:00 am to 6:00 pm ADT, which is 9:00 am to 4:00 pm CDT. Anything inside that window falls in the normal working day at both ends.
A note on AST: it can also mean Arabia Standard Time (UTC+3). This page means Atlantic Time.
A note on CST: it can also mean China Standard Time (UTC+8) and Cuba Standard Time (UTC−5). This page means US Central Time.
Atlantic Time (ADT) is used in Nova Scotia, New Brunswick and Puerto Rico
Central Time (CDT) is used in Dallas, Houston, Mexico City and Winnipeg