The majority of Argentina’s climate is subtropical The Patagonian provinces: Neuquén, Río Negro, Chubut, Santa Cruz and Tierra del Fuego, experience low rainfall, except in the strip adjacent to the Andes Mountains as well as in the southern end of the provinces of Santa Cruz and Tierra del Fuego. The contiguous strip of the Andes Mountains has abundant forests, glaciers and permanent snows, North of 40ºS, the climate is subtropical with hot summers. At the eastern end of this region there is abundant rainfall, which decreases towards the west and desert areas with very scarce vegetation, where cities and agriculture exist in the oases of the rivers fed by rainfall in the Cordillera; including provinces of San Juan, La Rioja, Catamarca and part of Mendoza. In the east, covering part of the provinces of Entre Rios, Buenos Aires, Santa Fe, Córdoba, La Pampa and San Luis, due to the humid conditions, rain-fed agriculture and cattle raising is extensive. The region between the humid east and the west arid is semi-arid, whose vegetation, originally from the mountains, has been modified by cattle breeding. In this region, the precipitation occurs almost entirely during the summer period. In the north of the country, in the province of Misiones and on the eastern slopes of the Tucumán, Salta and Jujuy, the high temperatures and abundant rainfall results in tropical forests. In Misiones, part of the original forest was replaced by commercial forestry, primarily pine. Commercial forestation of pines and eucalyptus also extends to the provinces of Corrientes and Entre Rios. The provinces of Chaco and Formosa, east of Salta and north of Santiago del Estero are in the region of the Chaco characterized by arboreal vegetation in the form of a park, where it is also develops extensive cattle raising and, increasingly, dry farming.
Argentina's climate features and seasonality are influenced by the presence of Los Andes Mountain extending along the west of the country as well as the El Niño-Southern Oscillation (ENSO) and the Indian Dipole. Sea surface temperature anomalies also influence Argentina’s weather. Additionally, warm (cold) phase of El Niño and a positive (negative) phase of Indian Dipole are all related to increased (decreased) spring and autumn precipitation in northeastern Argentina and Central Andes and the signal decreases in summer and winter.
- Argentina has experienced temperature increase since the 1960s, although warming trends are below global averages.
- In the majority of non-Patagonia areas of Argentina, temperature increases were observed at an average of 0.5ºC between 1960–2010; smaller increases were observed in the center of the country.
- In the Patagonia region, observed temperature increase was greater than in the rest of the country; with increases exceeding 1ºC.
- Extreme temperatures in the east and north of the country were also observed to increase, as well as the occurrence of more frequent heat waves and a reduction in frosts. While average temperature increases were below global mean increase, strong trends were observed for increases in extreme temperatures as well as heat waves over the past decades.
- Precipitation trends in Argentina are highly variable and affected by interannual and interdecadal variations.
- Between 1960 and 2010, mean annual precipitation was observed to increase. Largest observed changes (some in excess of 200 mm of rainfall) occurred in the east of the country as well as in semi-arid areas in the south.
- Since the early 1970s, the primary rivers of the Plata Basin have increased their mean flows, this was due not only to increased precipitation, but also to land use changes.
- Over the Andes Mountains, reduced rainfall and increased temperature have led to glaciers receding and reduced river flows.
- In the Patagonian Andes precipitation had a negative change in the period 1960–2010 and the rivers in northern Mendoza and San Juan seem to indicate reductions in precipitation (and water availability) in their upper basins over the Cordillera.
- The shift of more frequent and intense rainfall events in much of the country has been observed, which resulted in more frequent flooding.
- In the west and most notably in the north, the winter dry periods have become longer and drier, which has generated problems in the availability of water for some populations