Convert ACST to ACDT
ACDT is 1 hour ahead of ACST. ACST is UTC+9:30 and ACDT is UTC+10:30.
Right now: ACST · ACDT
Best time to schedule a meeting
Standard 9–5 working hours overlap for 7 hours: 9:00 AM–4:00 PM ACST (10:00 AM–5:00 PM ACDT). Schedule meetings inside that window.
| ACST | ACDT | Suitable? |
|---|---|---|
| 9:00 AM | 10:00 AM | working hours |
| 10:00 AM | 11:00 AM | working hours |
| 11:00 AM | 12:00 PM | working hours |
| 12:00 PM | 1:00 PM | working hours |
| 1:00 PM | 2:00 PM | working hours |
| 2:00 PM | 3:00 PM | working hours |
| 3:00 PM | 4:00 PM | working hours |
| 4:00 PM | 5:00 PM | outside 9–5 |
| 5:00 PM | 6:00 PM | outside 9–5 |
ACST to ACDT conversion table
| ACST | ACDT |
|---|---|
| 12:00 AM | 1:00 AM |
| 1:00 AM | 2:00 AM |
| 2:00 AM | 3:00 AM |
| 3:00 AM | 4:00 AM |
| 4:00 AM | 5:00 AM |
| 5:00 AM | 6:00 AM |
| 6:00 AM | 7:00 AM |
| 7:00 AM | 8:00 AM |
| 8:00 AM | 9:00 AM |
| 9:00 AM | 10:00 AM |
| 10:00 AM | 11:00 AM |
| 11:00 AM | 12:00 PM |
| 12:00 PM | 1:00 PM |
| 1:00 PM | 2:00 PM |
| 2:00 PM | 3:00 PM |
| 3:00 PM | 4:00 PM |
| 4:00 PM | 5:00 PM |
| 5:00 PM | 6:00 PM |
| 6:00 PM | 7:00 PM |
| 7:00 PM | 8:00 PM |
| 8:00 PM | 9:00 PM |
| 9:00 PM | 10:00 PM |
| 10:00 PM | 11:00 PM |
| 11:00 PM | 12:00 AM (next day) |
About ACST
Australian Central Standard Time (ACST) is UTC+9:30. It is used in Adelaide and Darwin in winter.
Australian Central Standard Time is UTC+9:30, half an hour behind the eastern states rather than a whole hour, which surprises people every time. South Australia moves to daylight saving in October and the Northern Territory does not, so Adelaide and Darwin share this offset for half the year and are an hour apart for the other half.
About ACDT
Australian Central Daylight Time (ACDT) is UTC+10:30. It is used in Adelaide in summer.
Australian Central Daylight Time is UTC+10:30, what South Australia keeps from October to April. Darwin stays on ACST through the summer, so for those months two cities in the same nominal zone are an hour apart — the only reason to be precise about which of the two abbreviations a meeting invitation carries.
Does this gap change with the seasons?
Neither ACST nor ACDT shifts with the seasons, so this 1-hour difference holds all year. That is unusual enough to be worth relying on: most cross-continental gaps move twice a year.
This is the reason scheduling systems store an IANA zone such as Region/City rather than an offset or an abbreviation: the zone knows its own rules and the offset does not.
Frequently asked questions
What time is 9:00 AM ACST in ACDT?
9:00 AM ACST is 10:00 AM ACDT.
Is ACDT ahead of ACST?
ACDT is 1 hour ahead of ACST.
Which time zone does this use?
ACST is UTC+9:30 and ACDT is UTC+10:30. Both abbreviations denote a single fixed offset, so this conversion never shifts with daylight saving — what changes is which abbreviation a place is using at the time.