Asia/Shanghai

TZ identifier and aliases

Asia/Shanghai is the canonical identifier for China Standard Time, legally covering the entire country. PRC is an older name still pointing at the same rules but is a deprecated alias; Asia/Chongqing, Asia/Harbin and the older spelling Asia/Chungking currently share identical rules and are folded into the same entry — use Asia/Shanghai in new code regardless of which Chinese city a system actually serves.

UTC offset and DST rule

Asia/Shanghai is +08:00 year-round with no daylight saving time. China briefly used DST in the 1980s but abolished it in 1991, and every region of the country — despite spanning roughly the same longitude range as the continental US — has used this single fixed offset ever since.

Using it in cron, CI and Postgres

Set TZ=Asia/Shanghai for a process that should schedule by Chinese local time — this is the correct identifier for any location in mainland China, including cities as far west as Ürümqi, roughly 3,000km from Shanghai itself, since China maintains only one legal time zone nationwide despite its geographic width. Postgres accepts it via SET TIME ZONE 'Asia/Shanghai'; 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 to account for.

History and quirks

China used five time zones under the Republic of China government before 1949; the incoming Communist government consolidated the entire country onto a single zone — Beijing Time, now designated Asia/Shanghai in the tz database — as a matter of national unity and administrative simplicity. The practical effect is stark in China's far west: in Ürümqi, solar noon can occur as late as 2:30pm on the official clock, since the city sits roughly two time zones' worth of longitude from Beijing. Xinjiang's Uyghur population unofficially keeps a separate "Xinjiang Time" (+06:00) in daily life for exactly this reason, even though it has no legal standing and doesn't appear as a separate entry in the tz database — a rare example of a widely-used local time convention that exists entirely outside any formally recognized zone identifier. Officially, every clock, train schedule and computer system in the country runs on Asia/Shanghai's single +08:00 offset.

Why the zone is named for Shanghai rather than Beijing, despite "Beijing Time" being the common spoken name for China's single offset, comes down to the tz database's general preference for a large, internationally recognizable city as a zone's label — Shanghai's role as China's largest city and primary financial center made it the practical choice for the IANA identifier even though the political capital and the colloquial name both point to Beijing instead. That naming mismatch trips up developers occasionally searching for Asia/Beijing, which doesn't exist as a valid IANA identifier at all — Asia/Shanghai is the only correct value for any China-wide scheduling system, regardless of which specific city a deployment actually serves.

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.