IANA tz database · zone identifier

Australia/Adelaide

The IANA tz database identifier for Australian Central Standard Time in Australia. Store this string — not the abbreviation, not the offset — and your timestamps stay correct forever.

UTC+09:30Abbreviation ACSTObserves daylight saving
Time in Australia/Adelaide☀ Daylight
08:28:05
Thursday, July 16, 2026
Offset
UTC+09:30
Abbreviation
ACST
DST
Observed

Current offset

UTC+09:30

standard UTC+09:30 · daylight UTC+10:30

Abbreviation

ACST

the standard-time form

DST behaviour

Observes

changes clocks twice a year

Country

🇦🇺 Australia

ISO 3166: AU · view country page →

Using this identifier

The string to put in your code.

Australia/Adelaide is the identifier to use in code and config for this region. Every modern language, database, and OS resolves it through the same tz database, so the examples here behave identically everywhere.

Avoid storing ACST or +09:30 — abbreviations are ambiguous and fixed offsets can't follow rule changes.

// format a date in this zone
new Intl.DateTimeFormat('en-US', {
timeZone: 'Australia/Adelaide',
dateStyle: 'full', timeStyle: 'long'
}).format(new Date());

Offset & DST behaviour

Two offsets,
every year.

Australia/Adelaide alternates between ACST (UTC+09:30) and ACDT (UTC+10:30). Right now it is on ACST; clocks spring forward on 4 October 2026.

The year at a glance

ACDT · UTC+10:30ACST · UTC+09:30ACDT · UTC+10:305 Apr · −1h4 Oct · +1h Jan 2026 Dec

Technical record

The database entry, in full.

source: IANA tz database

IdentifierAustralia/Adelaide
ISO country codeAU🇦🇺 Australia
Reference coordinates34.92°S, 138.58°Etz database reference point
Standard offsetUTC+09:30abbreviation ACST
Daylight offsetUTC+10:30abbreviation ACDT

Where it applies

One of Australia's 12 zones.

Looking for travel-friendly info? See Adelaide or Australian Central Standard Time.

🇦🇺
Australia

28M people, 12 time zones — this identifier covers one of them.

Country page →
🇦🇺 Adelaide
08:28
08:28:05 · ACST
pop. 1.4MACST

Related identifiers

Nearby in the database.

Same zone group · Australian Central Standard Time

other identifiers keeping ACST

Frequently asked questions

Answers specific to this identifier — generated from the database record. Can't find what you need? Email [email protected].

What UTC offset is Australia/Adelaide?
Australia/Adelaide is currently UTC+09:30 (ACST). It alternates between UTC+09:30 in winter and UTC+10:30 in summer.
Does Australia/Adelaide observe daylight saving time?
Yes. Clocks spring forward at the next transition on 4 October 2026, as they do twice every year.
Which country uses Australia/Adelaide?
Australia. It is one of 12 IANA zones covering the country.
Is Australia/Adelaide the same as ACST?
Australia/Adelaide is one of the IANA zones that keeps Australian Central Standard Time (ACST). Use Australia/Adelaide in software — ACST is a human-friendly label, not a valid identifier.

Free · Developer API

This zone, as JSON.

Everything on this page — offset, abbreviation, DST rules, coordinates — from one endpoint, always current with the latest tzdb release.

GET /v1/timezones Live

countries, cities, convert, DST transitions coming next.

Get your free API key →
// this identifier, resolved live
GET /v1/timezones?iana=Australia/Adelaide
{
"iana": "Australia/Adelaide",
"utc_offset": "+09:30",
"abbreviation": "ACST",
"observes_dst": true,
"country": "AU"
}