Argentina's climate is generally temperate, but there are great variations, from the extreme heat of the northern Chaco region, through the pleasant mild climate of the central pampas, to the subantarctic cold of the glacial regions of southern Patagonia. The highest temperature, 49° C (120° F ), was recorded in the extreme north, and the lowest,–16° C (3° F ), in the southern tip of the country. Rainfall diminishes from east to west. Rainfall at Buenos Aires averages 94 cm (37 in) annually, and the mean annual temperature is 16° C (61° F ). Light snowfalls occur occasionally in Buenos Aires. Throughout Argentina, January is the warmest month and June and July are the coldest. North of the Río Negro, the winter months (May–August) are the driest period of the year. The wide variations of climate are due to the great range in altitude and the vast extent of the country. In the torrid zone of the extreme north, for example, the Chaco area has a mean annual temperature of about 23° C (73° F ) and a rainfall of about 76 cm (30 in), whereas Puna de Atacama has a temperature average of 14° C (57° F ) and a rainfall of about 5 cm (2 in). The pampas, despite their immensity, have an almost uniform climate, with much sunshine and adequate precipitation. The coldest winters occur not in Tierra del Fuego, which is warmed by ocean currents, but in Santa Cruz Province, where the July average is 0° C (32° F ).