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DateAlmanac

What is ACST in HST?

Hawaii Standard Time is 20 hours 30 minutes behind

Australian Central Time is on UTC+10:30 and Hawaii Standard Time is on UTC−10:00 right now. Australian Central Time is on daylight saving, so its clocks read ACDT. The gap changes during the year — see below.

Convert a time

HST — Hawaii Standard Time

9:30 pm

HST, Fri, the previous day

Time in Adelaide
6:59:48 PM
Time in Honolulu
10:29:48 PM
Difference
−20:30 h
Next clock change
April 4, 2027

When the difference changes

Australian Central Time and Hawaii Standard 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:

  1. Now – April 4, 2027Hawaii Standard Time is 20 hours 30 minutes behind
  2. April 4, 2027 – October 3, 2027Hawaii Standard Time is 19 hours 30 minutes behind
  3. October 3, 2027 – onwardsHawaii Standard Time is 20 hours 30 minutes behind

Periods shorter than a day are not listed. Each zone changes at its own local time, so on a date when both move there are a few hours when the gap is briefly something else.

Daylight saving

Australian Central Time

Sunday, April 4, 2027

Clocks go back one hour — 3:00 am becomes 2:00 am local time, and the zone is on ACST after that.

Hawaii Standard Time

No clock changes

Hawaii Standard Time stays on HST all year, so its offset from UTC never moves.

ACST to HST conversion table

Every hour of Saturday, November 7, 2026, converted from Australian Central Time to Hawaii Standard Time. 21 of the 24 hours fall on a different calendar day in Honolulu, which is marked.

12:00 am ACDT
3:30 am HST−1 day
1:00 am ACDT
4:30 am HST−1 day
2:00 am ACDT
5:30 am HST−1 day
3:00 am ACDT
6:30 am HST−1 day
4:00 am ACDT
7:30 am HST−1 day
5:00 am ACDT
8:30 am HST−1 day
6:00 am ACDT
9:30 am HST−1 day
7:00 am ACDT
10:30 am HST−1 day
8:00 am ACDT
11:30 am HST−1 day
9:00 am ACDT
12:30 pm HST−1 day
10:00 am ACDT
1:30 pm HST−1 day
11:00 am ACDT
2:30 pm HST−1 day
12:00 pm ACDT
3:30 pm HST−1 day
1:00 pm ACDT
4:30 pm HST−1 day
2:00 pm ACDT
5:30 pm HST−1 day
3:00 pm ACDT
6:30 pm HST−1 day
4:00 pm ACDT
7:30 pm HST−1 day
5:00 pm ACDT
8:30 pm HST−1 day
6:00 pm ACDT
9:30 pm HST−1 day
7:00 pm ACDT
10:30 pm HST−1 day
8:00 pm ACDT
11:30 pm HST−1 day
9:00 pm ACDT
12:30 am HST
10:00 pm ACDT
1:30 am HST
11:00 pm ACDT
2:30 am HST

Scheduling between the two

Working hours overlap from 9:00 am to 3:00 pm ACDT, which is 12:30 pm to 6:30 pm HST. Anything inside that window falls in the normal working day at both ends.

Australian Central Time (ACDT) is used in South Australia and the Northern Territory, on a half-hour offset from the east coast

Hawaii Standard Time (HST) is used in all of Hawaii, which does not observe daylight saving

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