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.