America/Rosario

Time zone identifier: America/Rosario

Current civil offset: -03:00 (-03)

Current DST state: Observing Standard Time

First standard time adoption: Adopted on 1894-10-31

Local Mean Time (LMT): -04:16:48 based on geographic meridian

Total recorded transitions: 61 transitions across 4 distinct offsets

Historical Offset Step Chart (1880 to Present)

Text summary: America/Rosario shifted between 4 distinct offsets from 1894-10-31 through the modern era.

Complete Transition History (61 Transitions)

UTC Instant	Local Wall Time	Shift	Abbreviation	DST	Effect
`1894-10-31T04:16:48Z`	`1894-10-31 00:00:00`	-04:16:48 → -04:16:48	`CMT`	No	offset-only
`1920-05-01T04:16:48Z`	`1920-05-01 00:16:48`	-04:16:48 → -04:00	`-04`	No	gap
`1930-12-01T04:00:00Z`	`1930-12-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1931-04-01T03:00:00Z`	`1931-03-31 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1931-10-15T04:00:00Z`	`1931-10-15 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1932-03-01T03:00:00Z`	`1932-02-29 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1932-11-01T04:00:00Z`	`1932-11-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1933-03-01T03:00:00Z`	`1933-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1933-11-01T04:00:00Z`	`1933-11-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1934-03-01T03:00:00Z`	`1934-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1934-11-01T04:00:00Z`	`1934-11-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1935-03-01T03:00:00Z`	`1935-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1935-11-01T04:00:00Z`	`1935-11-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1936-03-01T03:00:00Z`	`1936-02-29 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1936-11-01T04:00:00Z`	`1936-11-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1937-03-01T03:00:00Z`	`1937-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1937-11-01T04:00:00Z`	`1937-11-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1938-03-01T03:00:00Z`	`1938-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1938-11-01T04:00:00Z`	`1938-11-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1939-03-01T03:00:00Z`	`1939-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1939-11-01T04:00:00Z`	`1939-11-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1940-03-01T03:00:00Z`	`1940-02-29 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1940-07-01T04:00:00Z`	`1940-07-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1941-06-15T03:00:00Z`	`1941-06-14 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1941-10-15T04:00:00Z`	`1941-10-15 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1943-08-01T03:00:00Z`	`1943-07-31 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1943-10-15T04:00:00Z`	`1943-10-15 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1946-03-01T03:00:00Z`	`1946-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1946-10-01T04:00:00Z`	`1946-10-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1963-10-01T03:00:00Z`	`1963-09-30 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1963-12-15T04:00:00Z`	`1963-12-15 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
`1964-10-15T04:00:00Z`	`1964-10-15 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1965-03-01T03:00:00Z`	`1965-02-28 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1965-10-15T04:00:00Z`	`1965-10-15 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
`1966-10-15T04:00:00Z`	`1966-10-15 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1967-04-02T03:00:00Z`	`1967-04-01 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1967-10-01T04:00:00Z`	`1967-10-01 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1968-04-07T03:00:00Z`	`1968-04-06 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1968-10-06T04:00:00Z`	`1968-10-06 01:00:00`	-04:00 → -03:00	`-03`	Yes	gap
`1969-04-06T03:00:00Z`	`1969-04-05 23:00:00`	-03:00 → -04:00	`-04`	No	overlap
`1969-10-05T04:00:00Z`	`1969-10-05 01:00:00`	-04:00 → -03:00	`-03`	No	gap
`1974-01-23T03:00:00Z`	`1974-01-23 01:00:00`	-03:00 → -02:00	`-02`	Yes	gap
`1974-05-01T02:00:00Z`	`1974-04-30 23:00:00`	-02:00 → -03:00	`-03`	No	overlap
`1988-12-01T03:00:00Z`	`1988-12-01 01:00:00`	-03:00 → -02:00	`-02`	Yes	gap
`1989-03-05T02:00:00Z`	`1989-03-04 23:00:00`	-02:00 → -03:00	`-03`	No	overlap
`1989-10-15T03:00:00Z`	`1989-10-15 01:00:00`	-03:00 → -02:00	`-02`	Yes	gap
`1990-03-04T02:00:00Z`	`1990-03-03 23:00:00`	-02:00 → -03:00	`-03`	No	overlap
`1990-10-21T03:00:00Z`	`1990-10-21 01:00:00`	-03:00 → -02:00	`-02`	Yes	gap
`1991-03-03T02:00:00Z`	`1991-03-02 22:00:00`	-02:00 → -04:00	`-04`	No	overlap
`1991-10-20T04:00:00Z`	`1991-10-20 02:00:00`	-04:00 → -02:00	`-02`	Yes	gap
`1992-03-01T02:00:00Z`	`1992-02-29 23:00:00`	-02:00 → -03:00	`-03`	No	overlap
`1992-10-18T03:00:00Z`	`1992-10-18 01:00:00`	-03:00 → -02:00	`-02`	Yes	gap
`1993-03-07T02:00:00Z`	`1993-03-06 23:00:00`	-02:00 → -03:00	`-03`	No	overlap
`1999-10-03T03:00:00Z`	`1999-10-03 00:00:00`	-03:00 → -03:00	`-03`	Yes	offset-only
`2000-03-03T03:00:00Z`	`2000-03-03 00:00:00`	-03:00 → -03:00	`-03`	No	offset-only
`2007-12-30T03:00:00Z`	`2007-12-30 01:00:00`	-03:00 → -02:00	`-02`	Yes	gap
`2008-03-16T02:00:00Z`	`2008-03-15 23:00:00`	-02:00 → -03:00	`-03`	No	overlap
`2008-10-19T03:00:00Z`	`2008-10-19 01:00:00`	-03:00 → -02:00	`-02`	Yes	gap
`2009-03-15T02:00:00Z`	`2009-03-14 23:00:00`	-02:00 → -03:00	`-03`	No	overlap

Notes from the Maintainers

Source: backzone (Lines 844 to 849)

Argentina
This entry was intended for the following areas, but has been superseded by
more detailed zones.
Santa Fe (SF), Entre Ríos (ER), Corrientes (CN), Misiones (MN), Chaco (CC),
Formosa (FM), La Pampa (LP), Chubut (CH)

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.