Asia/Vientiane

Time zone identifier: Asia/Vientiane

Current civil offset: +07:00 (+07)

Current DST state: Observing Standard Time

First standard time adoption: Adopted on 1906-06-30

Local Mean Time (LMT): +06:50:24 based on geographic meridian

Total recorded transitions: 7 transitions across 5 distinct offsets

Associated countries: LA

Historical Offset Step Chart (1880 to Present)

Text summary: Asia/Vientiane shifted between 5 distinct offsets from 1906-06-30 through the modern era.

Complete Transition History (7 Transitions)

UTC Instant	Local Wall Time	Shift	Abbreviation	DST	Effect
`1906-06-30T17:09:36Z`	`1906-07-01 00:16:06`	+06:50:24 → +07:06:30	`PLMT`	No	gap
`1911-04-30T16:53:30Z`	`1911-04-30 23:53:30`	+07:06:30 → +07:00	`+07`	No	overlap
`1942-12-31T16:00:00Z`	`1943-01-01 00:00:00`	+07:00 → +08:00	`+08`	No	gap
`1945-03-14T15:00:00Z`	`1945-03-15 00:00:00`	+08:00 → +09:00	`+09`	No	gap
`1945-09-01T15:00:00Z`	`1945-09-01 22:00:00`	+09:00 → +07:00	`+07`	No	overlap
`1947-03-31T17:00:00Z`	`1947-04-01 01:00:00`	+07:00 → +08:00	`+08`	No	gap
`1955-04-14T16:00:00Z`	`1955-04-14 23:00:00`	+08:00 → +07:00	`+07`	No	overlap

Notes from the Maintainers

Source: backzone (Lines 1130 to 1136)

Laos
From Paul Eggert (2014-10-11):
See Asia/Ho_Chi_Minh for the source for most of this data.
Trần's book says that Laos reverted to UT +07 on 1955-04-15.
Also, guess that Laos reverted to +07 on 1945-09-02, when Vietnam did;
this is probably wrong but it's better than guessing no transition.

Attributed Statements:

Paul Eggert (2014-10-11):

See Asia/Ho_Chi_Minh for the source for most of this data. Trần's book says that Laos reverted to UT +07 on 1955-04-15. Also, guess that Laos reverted to +07 on 1945-09-02, when Vietnam did; this is probably wrong but it's better than guessing no transition.

Years on Record

Methodology Note: The 1970 Rule

tzdb guarantees accuracy for timestamps from 1970 onwards. Transitions prior to 1970 represent best-effort historical reconstructions.