Pacific/Honolulu

TZ identifier and aliases

Pacific/Honolulu is the canonical identifier for Hawaii-Aleutian Standard Time. US/Hawaii, the bare POSIX name HST, and Pacific/Johnston (a now-uninhabited Pacific atoll that historically kept the same rules) all still resolve to the same offset but are deprecated aliases — use Pacific/Honolulu in new code.

UTC offset and DST rule

Pacific/Honolulu is -10:00 year-round with no daylight saving time — Hawaii is one of only two US states that opt out (Arizona is the other). Because it never shifts, its gap to mainland US zones widens and narrows twice a year purely because the mainland moves: Hawaii sits three hours behind Pacific Standard Time, but four hours behind once the mainland switches to Pacific Daylight Time each spring.

Using it in cron, CI and Postgres

Set TZ=Pacific/Honolulu for a process that should schedule by fixed Hawaii local time — naming the zone explicitly rather than hardcoding -10:00 keeps intent clear and stays correct automatically if the tz database is ever revised. Postgres accepts it via SET TIME ZONE 'Pacific/Honolulu'; or the timezone setting. Because this zone's offset never changes, it's one of the few in this family where a cron job's local-time schedule behaves identically on every calendar day — no 2am hour to avoid, no duplicated or skipped runs around a DST boundary. The only real gotcha for teams outside Hawaii is remembering that "Hawaii time" isn't a fixed number of hours behind Pacific or Eastern time across the whole year — it's fixed relative to UTC, but variable relative to any DST-observing US zone.

History and quirks

Hawaii briefly observed daylight saving during the WWII-era nationwide "War Time" period (1942–1945) and again for a single year under the original 1966 Uniform Time Act, before the state legislature exercised that Act's opt-out provision — a decision that made obvious sense given Hawaii's tropical latitude, where day length barely varies across the seasons and an extra hour of evening light in summer offers little benefit. The zone's name, "Hawaii-Aleutian Standard Time," reflects that it also technically covers Alaska's Aleutian Islands, a detail that predates the 1983 consolidation of Alaska's other time zones into America/Anchorage. At -10:00, Honolulu is the furthest-west (most negative) offset of any zone in this batch, putting it a full day behind much of Asia and Oceania even though the raw hour difference can look deceptively small.

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.