Timezone details
- Identifier
- Abbreviation
- —
- Transitioned
- May 31, 2021 at 10:30 AM
Australia • Darwin
AustraliaCurrent local time
13:44:33
Sunday, May 31, 2026
UTC offset
UTC+09:30
Darwin does not observe daylight saving time. Clocks stay on UTC+09:30 all year long.
Australian Central Standard Time (ACST)
Australian Central Standard Time (ACST) sits at UTC+09:30 and covers three mainland Australian zones — Adelaide, Broken Hill, and Darwin. It's one of the world's rare half-hour offset regions, splitting the gap between standard eastern and western Australia, making it a fascinating timezone quirk for global teams trying to slot meetings at the "quarter-to-ten" mark. Two of its three member zones observe daylight saving (Adelaide and Broken Hill), while Darwin stays on standard time year-round — so if you're scheduling with Central Australia, always double-check who's springing forward.
Australia spans three standard time zones, and the UTC+09:30 offset fills the geographic gap neatly between Western (UTC+08:00) and Eastern (UTC+10:00) — a practical compromise from the 19th century.
Adelaide and Broken Hill do — they switch to ACDT (UTC+10:30) in summer. Darwin (NT) does not, so during DST season, there's a 1-hour spread within the ACST code itself.
Daylight saving time for zones in South Australia ends on the first Sunday in April and starts again on the first Sunday in October, adding extra evening daylight during the southern hemisphere summer.
Not exactly — Broken Hill follows ACST with South Australia because it's closer to Adelaide than Sydney. It even shares South Australia's phone codes and relies on Adelaide-based TV and radio stations.
The UTC+09:30 offset places ACST ahead of most of Asia-Pacific during their workday. It aligns closely with Japan and South Korea at UTC+09:00, making ACST an easy slot for morning conference calls across the region.
Darwin is close to the equator, where daylight hours vary minimally year-round, so DST offers little benefit. Queensland also opted out of DST for similar practical reasons.
Half-hour offset timezones are rare worldwide, and ACST is one of the most well-known examples alongside India's IST (UTC+05:30) and Myanmar (UTC+06:30). It's a fun fact you've got at the 'quarter-to-ten' offset!
ACST is specific to Central Australia. While it covers a small number of official zones, it literally spans the continent — from South Australia's coast (Adelaide/Broken Hill) through to the tropical Northern Territory (Darwin).