America/Porto_Velho

Time zone identifier: America/Porto_Velho

Current civil offset: -04:00 (-04)

Current DST state: Observing Standard Time

First standard time adoption: Adopted on 1914-01-01

Local Mean Time (LMT): -04:15:36 based on geographic meridian

Total recorded transitions: 29 transitions across 3 distinct offsets

Associated countries: BR

Historical Offset Step Chart (1880 to Present)

Text summary: America/Porto_Velho shifted between 3 distinct offsets from 1914-01-01 through the modern era.

Complete Transition History (29 Transitions)

UTC Instant	Local Wall Time	Shift	Abbreviation	DST	Effect
`1914-01-01T04:15:36Z`	`1914-01-01 00:15:36`	-04:15:36 → -04:00	`-04`	No	gap
`1931-10-03T15:00:00Z`	`1931-10-03 12:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1932-04-01T03:00:00Z`	`1932-03-31 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1932-10-03T04:00:00Z`	`1932-10-03 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1933-04-01T03:00:00Z`	`1933-03-31 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1949-12-01T04:00:00Z`	`1949-12-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1950-04-16T04:00:00Z`	`1950-04-16 00:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1950-12-01T04:00:00Z`	`1950-12-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1951-04-01T03:00:00Z`	`1951-03-31 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1951-12-01T04:00:00Z`	`1951-12-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1952-04-01T03:00:00Z`	`1952-03-31 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1952-12-01T04:00:00Z`	`1952-12-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1953-03-01T03:00:00Z`	`1953-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1963-12-09T04:00:00Z`	`1963-12-09 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1964-03-01T03:00:00Z`	`1964-02-29 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1965-01-31T04:00:00Z`	`1965-01-31 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1965-03-31T03:00:00Z`	`1965-03-30 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1965-12-01T04:00:00Z`	`1965-12-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1966-03-01T03:00:00Z`	`1966-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1966-11-01T04:00:00Z`	`1966-11-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1967-03-01T03:00:00Z`	`1967-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1967-11-01T04:00:00Z`	`1967-11-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1968-03-01T03:00:00Z`	`1968-02-29 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1985-11-02T04:00:00Z`	`1985-11-02 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1986-03-15T03:00:00Z`	`1986-03-14 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1986-10-25T04:00:00Z`	`1986-10-25 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1987-02-14T03:00:00Z`	`1987-02-13 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1987-10-25T04:00:00Z`	`1987-10-25 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1988-02-07T03:00:00Z`	`1988-02-06 23:00:00`	-03:00 → -04:00	`-04`	No	overlap

Notes from the Maintainers

Source: southamerica (Lines 1057 to 1058)

Rondônia (RO)

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.