Asia/Pontianak

Time zone identifier: Asia/Pontianak

Current civil offset: +07:00 (WIB)

Current DST state: Observing Standard Time

First standard time adoption: Adopted on 1908-04-30

Local Mean Time (LMT): +07:17:20 based on geographic meridian

Total recorded transitions: 8 transitions across 5 distinct offsets

Associated countries: ID

Historical Offset Step Chart (1880 to Present)

Text summary: Asia/Pontianak shifted between 5 distinct offsets from 1908-04-30 through the modern era.

UTC Instant	Local Wall Time	Shift	Abbreviation	DST	Effect
`1908-04-30T16:42:40Z`	`1908-05-01 00:00:00`	+07:17:20 → +07:17:20	`PMT`	No	offset-only
`1932-10-31T16:42:40Z`	`1932-11-01 00:12:40`	+07:17:20 → +07:30	`+0730`	No	gap
`1942-01-28T16:30:00Z`	`1942-01-29 01:30:00`	+07:30 → +09:00	`+09`	No	gap
`1945-09-22T15:00:00Z`	`1945-09-22 22:30:00`	+09:00 → +07:30	`+0730`	No	overlap
`1948-04-30T16:30:00Z`	`1948-05-01 00:30:00`	+07:30 → +08:00	`+08`	No	gap
`1950-04-30T16:00:00Z`	`1950-04-30 23:30:00`	+08:00 → +07:30	`+0730`	No	overlap
`1963-12-31T16:30:00Z`	`1964-01-01 00:30:00`	+07:30 → +08:00	`WITA`	No	gap
`1987-12-31T16:00:00Z`	`1987-12-31 23:00:00`	+08:00 → +07:00	`WIB`	No	overlap

Source: asia (Lines 1364 to 1374)

Shanks & Pottenger say the next transition was at 1924 Jan 1 0:13,
but this must be a typo.
west and central Borneo

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