Argentina is located at a longitude that would naturally put it in the UTC−04:00 or UTC−05:00 time zone; however, it actually uses the UTC−03:00 time zone. Argentina determines whether to change clocks in observation of daylight saving time on a year-by-year basis, and individual provinces may opt out of the federal decision. At present, Argentina does not change clocks.

The Argentine Hydrographic ServiceHora Oficial maintains the official national time.

History The first official standardization of time in Argentina took place on 31 October 1894, with establishment of UTC−04:00 as the nation's standard time. From 1920 to 1969, the official time switched biannually between UTC−04:00 as standard time in winter and UTC−03:00 as daylight saving time in summer.Time Changes in Buenos Aires Over the Years, 1925–1949. TimeAndDate.com. From 1974 to 1993, clocks advanced again, such that the official time switched biannually between UTC−03:00 as winter DST and UTC−02:00 as summer double DST.Time Changes in Buenos Aires Over the Years, 1970–1979. TimeAndDate.com. In 1993, the national time was fixed at UTC−03:00, called Argentina Time (ART; ). In 2007 and 2008, biannual switching between UTC−3:00 (winter DST) and UTC−2:00 (summer DST) resumed; in 2009, this was replaced again with year-round UTC−3:00 (permanent DST).

IANA time zone database In the file zone.tab of the IANA time zone database Argentina has the following zones:

C.c.* Coordinates* TZ* Comments* UTC offset UTC offset DST Map

Full History + Full history of time zone changes since 1920 From the start of the day Adopted time zone Until the end of the day 01-05-1920 −4 30-11-1930 01-12-1930 −3 31-03-1931 01-04-1931 −4 14-10-1931 15-10-1931 −3 29-02-1932 01-03-1932 −4 31-10-1932 01-11-1932 −3 29-02-1933 01-03-1933 −4 31-10-1933 01-11-1933 −3 28-02-1934 01-03-1934 −4 31-10-1934 01-11-1934 −3 28-02-1935 01-03-1935 −4 31-10-1935 01-11-1935 −3 29-02-1936 01-03-1936 −4 31-10-1936 01-11-1936 −3 28-02-1937 01-03-1937 −4 31-10-1937 01-11-1937 −3 28-02-1938 01-03-1938 −4 31-10-1938 01-11-1938 −3 28-02-1939 01-03-1939 −4 31-10-1939 01-11-1939 −3 29-02-1940 01-03-1940 −4 30-06-1940 01-07-1940 −3 14-06-1941 15-06-1941 −4 14-10-1941 15-10-1941 −3 31-07-1943 01-08-1943 −4 14-10-1943 15-10-1943 −3 28-02-1946 01-03-1946 −4 30-09-1946 01-10-1946 −3 30-09-1963 01-10-1963 −4 14-12-1963 15-12-1963 −3 29-02-1964 01-03-1964 −4 14-10-1964 15-10-1964 −3 28-02-1965 01-03-1965 −4 14-10-1965 15-10-1965 −3 28-02-1966 01-03-1966 −4 14-10-1966 15-10-1966 −3 01-04-1967 02-04-1967 −4 30-09-1967 01-10-1967 −3 06-04-1968 07-04-1968 −4 05-10-1968 06-10-1968 −3 05-04-1969 06-04-1969 −4 04-10-1969 05-10-1969 −3 22-01-1974 23-01-1974 −2 30-04-1974 01-05-1974 −3 30-11-1988 01-12-1988 −2 04-03-1989 05-03-1989 −3 14-10-1989 15-10-1989 −2 03-03-1990 04-03-1990 −3 20-10-1990 21-10-1990 −2 02-03-1991 03-03-1991 −3 19-10-1991 20-10-1991 −2 29-02-1992 01-03-1992 −3 17-10-1992 18-10-1992 −2 06-03-1993 07-03-1993 −3 29-12-2007 30-12-2007 −2 15-03-2008 16-03-2008 −3 18-10-2008 19-10-2008 −2 14-03-2009 15-03-2009 −3 until the present

Notes

References

tz database – The tz database contains an extensive history of time zone and daylight saving time changes, with references to official sources for changes to time zones, for Argentina and the rest of the world.

External links Husos Horarios Adoptados en la República Argentina - Servicio de Hidrografía Naval, Ministerio de Defensa