Time Zone History

Argentina time zone history

Argentina has 12 zones of its own in the tz database. All of its zones keep UTC−3 as standard time, but their past clock changes differ. None of the 12 zones changes clocks today; the last seasonal change in any of them was in 2009. The San Luis zone has changed standard time most often since 1970: 8 times.

12 zones · 0 with seasonal clock changes under the rules in tzdata 2026f · Convert a time

The 12 zones of Argentina since 1970

the zone’s standard time today1 hour ahead1 hour behindthe zone’s standard time today1 hour ahead1 hour behind

How to read this chart

197019801990200020102020Buenos AiresCatamarcaCordobaJujuyLa RiojaMendozaRio GallegosSaltaSan JuanSan LuisTucumánUshuaia197019902010Buenos AiresCatamarcaCordobaJujuyLa RiojaMendozaRio GallegosSaltaSan JuanSan LuisTucumánUshuaia

Zones at a glance

ZoneArea coveredStandard timeClock changes todayNew standard times since 1970
Buenos AiresBuenos Aires city and provinceUTC−3no, last in 20092
CatamarcaCatamarca and ChubutUTC−3no, last in 20086
CordobaMost provinces: Córdoba, Chaco, Corrientes, Entre Ríos, Formosa, Misiones, Santiago del Estero, Santa FeUTC−3no, last in 20094
JujuyJujuyUTC−3no, last in 20084
La RiojaLa RiojaUTC−3no, last in 20086
MendozaMendozaUTC−3no, last in 20086
Rio GallegosSanta CruzUTC−3no, last in 20084
SaltaSalta, La Pampa, Neuquén, Río NegroUTC−3no, last in 20084
San JuanSan JuanUTC−3no, last in 20086
San LuisSan LuisUTC−3no, last in 20098
TucumánTucumánUTC−3no, last in 20096
UshuaiaTierra del FuegoUTC−3no, last in 20084

What sets each zone apart

  • Buenos Aires: Daylight saving time was used in 12 years since 1970, last in 2009; under the current rules the clocks no longer change.
  • Catamarca: Daylight saving time was used in 11 years since 1970, last in 2008; under the current rules the clocks no longer change.
  • Cordoba: Daylight saving time was used in 12 years since 1970, last in 2009; under the current rules the clocks no longer change.
  • Jujuy: Daylight saving time was used in 11 years since 1970, last in 2008; under the current rules the clocks no longer change.
  • La Rioja: Daylight saving time was used in 11 years since 1970, last in 2008; under the current rules the clocks no longer change.
  • Mendoza: On standard time, clocks at Mendoza run 1 hour 35 minutes ahead of local mean solar time, the second-largest gap of the 12 zones in Argentina. Daylight saving time was used in 11 years since 1970, last in 2008; under the current rules the clocks no longer change.
  • Rio Gallegos: On standard time, clocks at Rio Gallegos run 1 hour 37 minutes ahead of local mean solar time, the tenth-largest gap of the 233 zones whose clocks run ahead of the sun. Daylight saving time was used in 11 years since 1970, last in 2008; under the current rules the clocks no longer change.
  • Salta: Daylight saving time was used in 11 years since 1970, last in 2008; under the current rules the clocks no longer change.
  • San Juan: On standard time, clocks at San Juan run 1 hour 34 minutes ahead of local mean solar time, the third-largest gap of the 12 zones in Argentina. Daylight saving time was used in 11 years since 1970, last in 2008; under the current rules the clocks no longer change.
  • San Luis: The San Luis zone has changed its standard time 8 times since 1970, tied second-most among all 312 zones. Daylight saving time was used in 10 years since 1970, last in 2009; under the current rules the clocks no longer change.
  • Tucumán: Clocks have been changed 20 times since 1970, the most of the 12 zones in Argentina. Daylight saving time was used in 12 years since 1970, last in 2009; under the current rules the clocks no longer change.
  • Ushuaia: Daylight saving time was used in 11 years since 1970, last in 2008; under the current rules the clocks no longer change.

How the zones compare with Buenos Aires since 1970

  • Cordoba: same time as Buenos Aires except 231 days in 1991.
  • Salta: same time as Buenos Aires except 378 days in 1991, 2008 and 2009.
  • Jujuy: same time as Buenos Aires except 728 days in 1990, 1991, 2008 and 2009.
  • Tucumán: same time as Buenos Aires except 243 days in 1991 and 2004.
  • Catamarca: same time as Buenos Aires except 397 days in 1991, 2004, 2008 and 2009.
  • La Rioja: same time as Buenos Aires except 233 days in 1991, 2004, 2008 and 2009.
  • San Juan: same time as Buenos Aires except 269 days in 1991, 2004, 2008 and 2009.
  • Mendoza: same time as Buenos Aires except 1,221 days in 1990–1992, 2004, 2008 and 2009.
  • San Luis: same time as Buenos Aires except 1,398 days in 1990–1993, 2004, 2008 and 2009.
  • Rio Gallegos: same time as Buenos Aires except 166 days in 2004, 2008 and 2009.
  • Ushuaia: same time as Buenos Aires except 168 days in 2004, 2008 and 2009.

Every change of standard time since 1970

60 changes across the 12 zones, oldest first.

  • March 4, 1990 Jujuy: UTC−3 to UTC−4
  • March 4, 1990 Mendoza: UTC−3 to UTC−4
  • March 14, 1990 San Luis: UTC−3 to UTC−4
  • March 1, 1991 La Rioja: UTC−3 to UTC−4
  • March 1, 1991 San Juan: UTC−3 to UTC−4
  • March 3, 1991 Catamarca: UTC−3 to UTC−4
  • March 3, 1991 Cordoba: UTC−3 to UTC−4
  • March 3, 1991 Salta: UTC−3 to UTC−4
  • March 3, 1991 Tucumán: UTC−3 to UTC−4
  • May 7, 1991 La Rioja: UTC−4 to UTC−3
  • May 7, 1991 San Juan: UTC−4 to UTC−3
  • June 1, 1991 San Luis: UTC−4 to UTC−3
  • October 6, 1991 Jujuy: UTC−4 to UTC−3
  • October 20, 1991 Catamarca: UTC−4 to UTC−3
  • October 20, 1991 Cordoba: UTC−4 to UTC−3
  • October 20, 1991 Salta: UTC−4 to UTC−3
  • October 20, 1991 Tucumán: UTC−4 to UTC−3
  • October 18, 1992 Mendoza: UTC−4 to UTC−3
  • October 3, 1999 Buenos Aires: summer offset kept as standard time
  • October 3, 1999 Catamarca: summer offset kept as standard time
  • October 3, 1999 Cordoba: summer offset kept as standard time
  • October 3, 1999 Jujuy: summer offset kept as standard time
  • October 3, 1999 La Rioja: summer offset kept as standard time
  • October 3, 1999 Mendoza: summer offset kept as standard time
  • October 3, 1999 Rio Gallegos: summer offset kept as standard time
  • October 3, 1999 Salta: summer offset kept as standard time
  • October 3, 1999 San Juan: summer offset kept as standard time
  • October 3, 1999 San Luis: summer offset kept as standard time
  • October 3, 1999 Tucumán: summer offset kept as standard time
  • October 3, 1999 Ushuaia: summer offset kept as standard time
  • March 3, 2000 Buenos Aires: summer offset kept as standard time
  • March 3, 2000 Catamarca: summer offset kept as standard time
  • March 3, 2000 Cordoba: summer offset kept as standard time
  • March 3, 2000 Jujuy: summer offset kept as standard time
  • March 3, 2000 La Rioja: summer offset kept as standard time
  • March 3, 2000 Mendoza: summer offset kept as standard time
  • March 3, 2000 Rio Gallegos: summer offset kept as standard time
  • March 3, 2000 Salta: summer offset kept as standard time
  • March 3, 2000 San Juan: summer offset kept as standard time
  • March 3, 2000 San Luis: summer offset kept as standard time
  • March 3, 2000 Tucumán: summer offset kept as standard time
  • March 3, 2000 Ushuaia: summer offset kept as standard time
  • May 23, 2004 Mendoza: UTC−3 to UTC−4
  • May 30, 2004 Ushuaia: UTC−3 to UTC−4
  • May 31, 2004 San Juan: UTC−3 to UTC−4
  • May 31, 2004 San Luis: UTC−3 to UTC−4
  • June 1, 2004 Catamarca: UTC−3 to UTC−4
  • June 1, 2004 La Rioja: UTC−3 to UTC−4
  • June 1, 2004 Rio Gallegos: UTC−3 to UTC−4
  • June 1, 2004 Tucumán: UTC−3 to UTC−4
  • June 13, 2004 Tucumán: UTC−4 to UTC−3
  • June 20, 2004 Catamarca: UTC−4 to UTC−3
  • June 20, 2004 La Rioja: UTC−4 to UTC−3
  • June 20, 2004 Rio Gallegos: UTC−4 to UTC−3
  • June 20, 2004 Ushuaia: UTC−4 to UTC−3
  • July 25, 2004 San Juan: UTC−4 to UTC−3
  • July 25, 2004 San Luis: UTC−4 to UTC−3
  • September 26, 2004 Mendoza: UTC−4 to UTC−3
  • January 21, 2008 San Luis: UTC−3 to UTC−4
  • October 11, 2009 San Luis: UTC−4 to UTC−3