Mendoza Province - Geography and Climate

Geography and Climate

The geography of the province descends from 6,959 metres (22,831 ft) at the summit of Aconcagua to the semi-flat lands of the east. A series of longitudinal valles, such as the Uspallata, separate the Andes from the Precordillera lower mountains. To the east, the Cuyean plains are crossed by tributaries of the Desaguadero River. Other important rivers include Mendoza River, Tunuyán River, Diamante River and Atuel River.

The climate is continental, sunny and dry in the entire territory of the province, with warm summers and relatively cold winters. The arid soil due to the scant precipitation and the great temperature difference between day and night allows mainly xerophytes and few trees to grow. The annual precipitation lies between 150 and 350mm, and hail is a significant, and not uncommon, problem in the regional viticulture. There are fertile lands surrounding the basins of the many rivers born in the glaciers of the Cordillera.

The lowlands have very hot summers (30°C to 33°C during the day, or 86F to 91F) with warm nights in the north (18°C, or 64F) and cooler evenings in the south (15°C, 59F). Precipitation falls mainly as very scarce, but often severe thunderstorms that bring hail and high winds. Falls are pleasant and dry, and winters are cool with daytime highs around 14°C (57F) and nighttime lows of 2°C (35F). When Zonda winds blow downslope from the Andes, temperatures may soar to 30°C (86F); however, Pampero winds can keep day temperatures below 5°C (41F) and nighttime lows of -8°C (18F) can be recorded. Snow is uncommon in the north, and occasional in the south.

The area around Malargue is located at higher elevation (1400 meters) and thus the weather is significantly colder: summers average 28°C (82F) during the day, but only 11°C (53F) at night, and winters range from 10°C (50F) to -2°C (28F). Here, precipitation is somewhat higher (350 mm) and winter is stormier than the summer, with 45 mm (1.8 in) falling in July. Snow is much more common, and falls several times every year: on occasion, it can be heavy. Temperatures often fall to -12°C (10F) and up to -23°C (-9F) have been recorded.

The first slopes of the Andes are dry and sunny; however, precipitation increases as one approaches the border with Chile, especially toward the south, where some areas receive over 600 mm (24 in), falling exclusively in the winter, and mostly as snow. Altitudes over 2,600 m in the north and over 2,000 m in the far south usually have ample snow cover. Summer days may be warm and sunny, but nights are always cold, whereas winter temperatures tend to be moderate, with long stretches of sunny (but very windy) weather alternating with very intense snowstorms where several meters of snow may pile up, providing excellent skiing conditions in resorts like Las Lenas, Penitentes and Vallecitos. Mountains often surpass 5,000 meters, and Aconcagua reaches 6,959 meters: at these altitudes, the climate is extremely cold and windy year round, with temperatures down to -40°C.

Different wind fronts affect the landscape, mainly the Zonda wind, but also the mild Pampero, the warm Viento Norte and, in winter, the very rare Sudestada from the Southeast. The latter wind mostly affects the pampas.