ACST: Australian Central Standard Time
ACST is Australian Central Standard Time, +09:30, used in Oceania. In code, use Australia/Adelaide rather than the abbreviation.
Australian Central Standard Time · Oceania
11:15:49
Sunday, 27 September 2026
- abbreviation denotes
- +09:30
- in force right now
- ACST (UTC+09:30)
- use in code
- Australia/Adelaide
- also valid
- Australia/Darwin
- next clock change
- 4 Oct 2026 03:00 → ACDT
Use the IANA name, not the abbreviation
Python
from datetime import datetime
from zoneinfo import ZoneInfo
# right: an IANA zone carries the full history of rule changes
now = datetime.now(ZoneInfo("Australia/Adelaide"))
print(now.isoformat(), now.tzname())
# wrong: an abbreviation is not resolvable, and a hard-coded offset
# silently rots the next time the rules change
# now = datetime.now(timezone(timedelta(hours=...))) # don'tACST questions
What does ACST stand for?
ACST is Australian Central Standard Time, +09:30, used in Oceania. The IANA zone to use in code is Australia/Adelaide.
What time is it in ACST right now?
Australian Central Standard Time: 11:15 on Sunday (ACST).
Which IANA timezone should I use instead of ACST?
Australia/Adelaide for Australian Central Standard Time. Date libraries cannot resolve bare abbreviations, and an abbreviation carries no daylight-saving history, so a stored offset silently rots when a government changes the rules.