Australia/Perth

TZ identifier and aliases

Australia/Perth is the canonical identifier for Western Australian time. Australia/West is an older name still pointing at the same rules but is a deprecated alias — use Australia/Perth in new code.

UTC offset and DST rule

Australia/Perth is +08:00 year-round with no daylight saving time. Western Australia has held three separate referendums on adopting DST — most recently in 2009 — and voters rejected it each time, so there's no seasonal clock change to account for in any system built against this zone.

Using it in cron, CI and Postgres

Set TZ=Australia/Perth for a process that should schedule by Western Australian local time. Postgres accepts it via SET TIME ZONE 'Australia/Perth'; or the timezone setting. Because the offset never changes, a cron job's local-time schedule behaves identically every day of the year, with no DST boundary or skipped/duplicated hour to plan around — a genuine operational simplicity that stands out against Australia/Sydney's reversed-calendar DST rule on the other side of the country.

History and quirks

Western Australia's rejection of daylight saving isn't for lack of trying: the state has put DST to a public referendum three times — in 1975, 1992 and 2009 — and voters said no each time, most recently by a roughly 55–45 margin. Much of the opposition traces to the state's sheer size and low population density outside Perth: northern, more tropical regions of Western Australia see little seasonal daylight variation and gain nothing from DST, while agricultural interests have historically argued that shifting clocks disrupts livestock routines and harvest timing. The practical result is a three-hour spread across mainland Australia during the eastern states' DST months — Perth at +08:00, Adelaide at +10:30, Sydney at +11:00 — compared to just a two-hour spread the rest of the year, making cross-country scheduling within Australia itself meaningfully harder for roughly half of each year than the other half.

Perth's isolation is also geographic, not just political: it's among the most remote major cities in the world relative to any other city of comparable size, sitting closer in straight-line distance to Jakarta or Singapore than to Sydney or Melbourne, which adds a practical dimension to the state's DST skepticism — Perth's natural business-hours overlap already leans toward Southeast Asia more than toward Australia's own eastern seaboard, and adding a seasonal clock shift would only complicate that further without a clear corresponding benefit. Australia/Perth's stability also makes it a reliable reference point for any system needing a fixed Western Australian anchor, in contrast to the reversed-calendar, twice-yearly complexity of Australia/Sydney just a few states away.

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.