Salta Province - Geography and Climate

Geography and Climate

The province is located on the tropic of Capricorn, and receives both tropical and temperate influences. There are five main climates in the province: the climate of the Impenetrable to the east, the Yungas, the climate of low valleys (Valles Calchaquies, Valle de Lerma), the climate of the Altiplano, and the climate of the highest peaks.

The Impenetrable region has one of the most extreme climates in South America. Winters are pleasant but short, with high temperatures usually between 18°C and 25°C (64F to 77F) and lows between 7°C and 14°C (45F to 57F). Temperatures can soar to 35°C (95F) or reach below 0°C (32F) on occasion. The main feature of the cool season is its marked dryness. Spring is even dryer than winter, and high temperatures quickly reach averages of 28°C (82F) in September, 31°C (88F) in October and 34°C (93F) in November. This, combined to the extreme dryness, produces a very severe drought. Summer runs from November till April, and is characterized by the extreme heat and the severe thunderstorms: 80% of yearly precipitation falls in this season, and average maximum temperatures reach 37°C (99F) with lows of 23°C (73F) and very high humidity. Thus, extremely oppressive weather lasts for over 6 months in the region. During heat waves, over 45°C (113F) are reached. Fall arrives suddenly in April with more pleasant, dry weather, and by late May, winter conditions settle. Precipitation ranges from 500 mm (20 in) to 700 mm (28 in).

The first slopes of the Andes force the moist, easterly winds to rise, provoking very high condensation. At low altitudes, the climate is still hot during most of the year, but the increased storminess greatly moderates high temperatures: the average high in midsummer is 33°C (91F), and total rainfall ranges from 900 mm to over 2,000 mm, creating a thick jungle called Yunga. At higher altitudes, the weather is much cooler and there is a layer that is constantly immersed in a cloud for several months, creating a unique environment with ferns, mosses and parasitic plants growing on trees. As we reach over 1,000 meters, frost is much more common and the jungle starts giving way to a temperate forest, and at higher altitudes, snow may fall in the winter, and trees give way to alpine meadows.

The overwhelming majority of Salta's population (including the capital city) lives in the valleys at altitudes between 1,000 and 1,500 meters above sea level. The climate here is known for being pleasant and suitable for agriculture and human settlement: winters are mild during the day (average of 19°C, 66F, occasionally over 25°C or 77F, but sometimes staying below 5°C, 41F), cold at night (3°C, or 37F, with temperatures below -5°C (23F) often recorded), and very low precipitation falling mostly as light rain (although snow is possible, but very rare). Summers are rainy and very moderate, with highs of 28°C (82F) and lows of 15°C (59F), very common thunderstorms and intense solar radiation. Precipitation ranges from 750 mm to 1,000 mm.

Further west, the Altiplano is a plateau at 3,000 m to 4,000 m above sea level. The climate is arid and cold: high temperatures vary little (since the warmer season is cloudy, and the coolest is sunny), ranging from 14°C to 21°C (57F to 70F), night temperatures go from 6°C (43F) in midsummer to -8°C (18F) in midwinter, and extremes under -15°C (5F) might be recorded. All rain falls exclusively in the summer, with values between 200 mm and 400 mm in total. Several salt flats exist in this area.

Finally, the highest peaks of the province reach over 6,000 meters above sea level: they are constantly snow covered, and temperatures rarely approach the 0°C (32F) mark, with constant high winds, extreme aridity and high solar radiation.

The main rivers of the province are the Pilcomayo, Bermejo and the Juramento, which later becomes the Salado River. Salta Province is located at a geologically active region, and suffers from occasional earthquakes. Fairly destructive were the ones that occurred in 1692 and 1948.