What is MST in ACST?
Australian Central Time is 15 hours 30 minutes ahead
Mountain Time is on UTC−6:00 and Australian Central Time is on UTC+9:30 right now. Mountain Time is on daylight saving, so its clocks read MDT. The gap changes during the year — see below.
- Time in Denver
- 8:56 pm
- Time in Adelaide
- 12:26 pm
- Difference
- +15:30 h
- Next clock change
- October 3, 2026
Convert a time
ACST — Australian Central Time
11:30 am
Wed, the next day
When the difference changes
Mountain Time and Australian Central Time do not change their clocks on the same dates, so the gap between them is not the same all year. Most converters show only today’s figure. These are the periods ahead:
- Now – October 3, 2026Australian Central Time is 15 hours 30 minutes ahead
- October 3, 2026 – November 1, 2026Australian Central Time is 16 hours 30 minutes ahead
- November 1, 2026 – March 14, 2027Australian Central Time is 17 hours 30 minutes ahead
- March 14, 2027 – April 3, 2027Australian Central Time is 16 hours 30 minutes ahead
- April 3, 2027 – October 2, 2027Australian Central Time is 15 hours 30 minutes ahead
- October 2, 2027 – onwardsAustralian Central Time is 16 hours 30 minutes ahead
Periods shorter than a day are not listed: both zones change at 2am in their own local time, so there are a few hours on each transition date when the gap is briefly something else.
Daylight saving
Mountain Time
Clocks go back one hour at 2am local time, becoming MST.
Australian Central Time
Clocks go forward one hour at 2am local time, becoming ACDT.
MST to ACST conversion table
Every hour of Tuesday, September 22, 2026, converted from Mountain Time to Australian Central Time. 15 of the 24 hours fall on a different calendar day in Adelaide, which is marked.
- 12:00 am MDT
- 3:30 pm ACST
- 1:00 am MDT
- 4:30 pm ACST
- 2:00 am MDT
- 5:30 pm ACST
- 3:00 am MDT
- 6:30 pm ACST
- 4:00 am MDT
- 7:30 pm ACST
- 5:00 am MDT
- 8:30 pm ACST
- 6:00 am MDT
- 9:30 pm ACST
- 7:00 am MDT
- 10:30 pm ACST
- 8:00 am MDT
- 11:30 pm ACST
- 9:00 am MDT
- 12:30 am ACST+1 day
- 10:00 am MDT
- 1:30 am ACST+1 day
- 11:00 am MDT
- 2:30 am ACST+1 day
- 12:00 pm MDT
- 3:30 am ACST+1 day
- 1:00 pm MDT
- 4:30 am ACST+1 day
- 2:00 pm MDT
- 5:30 am ACST+1 day
- 3:00 pm MDT
- 6:30 am ACST+1 day
- 4:00 pm MDT
- 7:30 am ACST+1 day
- 5:00 pm MDT
- 8:30 am ACST+1 day
- 6:00 pm MDT
- 9:30 am ACST+1 day
- 7:00 pm MDT
- 10:30 am ACST+1 day
- 8:00 pm MDT
- 11:30 am ACST+1 day
- 9:00 pm MDT
- 12:30 pm ACST+1 day
- 10:00 pm MDT
- 1:30 pm ACST+1 day
- 11:00 pm MDT
- 2:30 pm ACST+1 day
Scheduling between the two
There is no overlap between a nine-to-six working day in Denver and one in Adelaide — the gap is too wide. A call has to sit early or late for one side. Early morning in Denver is the usual compromise, since that is late afternoon or evening in Adelaide.
Mountain Time (MDT) is used in Salt Lake City, Albuquerque and Calgary. Arizona keeps MST all year and does not follow MDT.
Australian Central Time (ACST) is used in South Australia and the Northern Territory, on a half-hour offset from the east coast