region while during the dry years, these winds are weaker. Summers in the region are hot and generally very sunny, averaging as much as 10 hours per day. In contrast, winters are dry and cold and average around 7–8 hours of sunshine per day. Since this region has a wide range of elevations, ranging from 500 m to nearly 7,000 m, temperatures can vary widely with elevation. In the lowlands of Mendoza province, which lie at an elevation of around 440 m to 530 m, mean annual temperatures range from in the northern parts to in the south. At higher elevation locations and in the western parts of Mendoza province, the mean annual temperatures range from in Cristo Redentor to with a larger difference in temperatures between winter and summer months. In San Juan Province, the mean annual temperature ranges from in the provincial capital to . In San Luis province, mean annual temperatures range from in Villa Reynolds to in the provincial capital. The Sierras Pampeanas, which cross into both San Juan province and San Luis province have a milder climate with mean annual temperatures ranging from . In all locations, at elevations over 3,800 m, permafrost is present while icy conditions persist year round at elevations over 4,000 m. The Zonda, a Foehn wind characterized by warm, dry air can cause temperatures to exceed in some cases while in summer, temperatures can exceed such as in 2003. This wind often precedes following a cold front passage across Argentina and tends to occur when a low pressure system brings heavy rain to the Chilean side, and when an upper level trough allows the winds to pass over the Andes to descend downwards. As such, when a zonda wind event occurs, the temperature may raise as much as in a few hours with humidity approaching 0%. In contrast, cold waves are also common, owing to the Andes channeling cold air from the south, allowing cold fronts to frequently come during the winter months, causing cool to cold temperatures with temperatures that can fall below freezing. Temperatures can dip below at the higher elevations. Tourism As in other parts of Argentina, nature tourism is an important source of income. Amongst sites that receive a large number of visitors, the following are its main attractions: Aconcagua Fiesta Nacional de la Vendimia Las Leñas Biosphere Reserve of Ñacuñán San Rafael Barreal Difunta Correa