The climate that affects the protected area that we analyze can be classified as a Temperate semi-arid mountain. It is characterized by the irregularity of the rainfall regime that the variations that, in this aspect, suffer from the area due to the climatic influence of the Atlantic domain, with summer rains, and the Pacific domain with its predominantly winter rainfall. Important in the Aconcagua treks.
Despite the great distance that separates it from the Atlantic, this mountainous part receives from that sector the low humidity that generally precipitates in the form of significant snowfalls in the highest positions, during May to August mostly. Its frequency and magnitude decrease towards the east.
From the Pacific, the climate is most influenced by the action of the Pacific anticyclone that generates westerly winds. These winds rise, and when they collide with the hills of the mountain range. The Chilean coast is affected by two well-differentiated currents, the Humbold one, the southern sector. Depending on the origin of the wind, both influence the area, although, to a much greater extent, the winds of the southwestern sector are necessary for the Aconcagua Mountain guides.
In the mountain range, the ascent of the air is made markedly through the hills’ valleys and slopes, and due to the low pressure that exists in the summits, this air generally rises during the afternoons and forms accumulations but is not produced. At night the opposite phenomenon occurs, and the wind blows from the top towards the valleys.
Like all regions with marked altitudinal variations, the temperature is a climatic factor dependent on them.
In the entire Cuyana mountain range, strong cold winds from the west and south-west sector occur in winter, which when they blow together with snowfalls, the dreaded white wind is formed. Under particular atmospheric conditions, these same winds cross the Before undergoing abrupt changes that make them hot and dry when they reach the lowlands, as occurs with the folkloric Zonda wind.
As for the summer temperatures, it must be taken into account that during the nights, over 5,000 m.a.s.l. -20 ° C is a non-exceptional value, and at the top, it reaches -30 ° C. In Plaza de Mulas, in times of bad weather conditions are usually –18 C °. During winter, the area is heavily covered with snow, and the temperature rarely exceeds 0 ° C. the location area of the Aconcagua Ascents Provincial Park allows it to be classified phytogeographically according to Cabrera (1976) .in what he calls the High Andean Province, which encompasses all the high mountains that are located west of Argentina from the Bolivian territory to Tierra del Fuego. According to the latitude, this biome is divided into districts, denominating the High Andean Cuyano District that occupies the Andes of San Juan and Mendoza provinces. The classification made by PRODIA (1999) does not differ too much from the one mentioned above, only that the latter starts at approximately 38º Lat.S. towards the south, it ceases to be called the Eco-region of the High Andes to be called the Patagonian Forests, due to the presence of the Valdivian jungle in this sector.