Australia/Sydney

TZ identifier and aliases

Australia/Sydney is the canonical identifier for Australian Eastern Time, covering New South Wales, Victoria and Tasmania. Australia/Melbourne, Australia/Hobart, Australia/Currie and the state-abbreviation links Australia/ACT, Australia/NSW, Australia/Victoria and Australia/Tasmania currently share identical rules and are folded into the same entry — all deprecated in favor of Australia/Sydney in new code.

UTC offset and DST rule

Australia/Sydney is +11:00 (AEDT) during daylight saving and +10:00 (AEST) on standard time — note the offset is higher in summer here, opposite to how it reads in the northern hemisphere, because Australia's summer falls in the December–February window. DST runs from the first Sunday in October to the first Sunday in April — October 4 and April 5 in 2026 — the reverse direction of the US/EU calendar entirely.

Using it in cron, CI and Postgres

Set TZ=Australia/Sydney for a process that should schedule by Sydney/Melbourne local time — code written with a northern-hemisphere mental model of "DST is summer, summer is June–August" will misread this zone's calendar, since Sydney's DST window spans the October–April Australian summer instead. Postgres accepts it via SET TIME ZONE 'Australia/Sydney'; or the timezone setting and applies the correct southern-hemisphere rule automatically. Where a scheduler supports a CRON_TZ=Australia/Sydney line, jobs run by local time directly; GitHub Actions' schedule: trigger always evaluates in UTC, so a fixed-local-hour job needs its UTC equivalent recalculated across each transition, keeping in mind the direction is reversed from Europe's.

History and quirks

Australia's DST rule isn't actually national — it's set state by state, which is why Australia/Sydney covers New South Wales, Victoria and Tasmania but not Queensland or Western Australia, both of which keep fixed standard time year-round with no DST at all. That patchwork means for part of the year, Queensland (just north of New South Wales) is on a different clock than Sydney despite sharing a land border, purely because Queensland voters rejected DST in a 1992 referendum and have kept rejecting it in later polling, citing concerns from the state's northern, more tropical regions where day-length barely varies. Australia/Sydney's reversed DST calendar relative to the northern hemisphere is a frequent source of off-by-a-season bugs in international scheduling software that assumes every DST-observing zone follows the US/EU pattern.

Adelaide adds a further wrinkle just west of this zone: South Australia observes the same October-to-April DST window as Sydney but sits on a half-hour-offset base (+09:30/+10:30), so in summer the east and south of the country run +10:00 (Queensland), +10:30 (South Australia) and +11:00 (Sydney) side by side, compressed into a relatively narrow band of states. Combined with Queensland and Western Australia's no-DST stance, Australia routinely runs five distinct civil time offsets simultaneously for part of the year and three for the rest — an unusually fragmented pattern for a single federated country, and one worth testing against explicitly for any software handling Australia-wide scheduling rather than assuming a single national offset applies.

Offsets and DST transitions on this page are computed from the IANA time zone database bundled with your browser; the rules described above were verified against tzdata 2026b when this page was published.