Although Bolivia lies entirely in the tropics, extreme differences in altitude and rainfall give it a great variety in climate. The mean annual temperature of La Paz, at 3,697 m (12,130 ft), is about 8°c (46°f) and in the eastern lowlands is 26°c (79°f). In the western highlands, cold winds blow all year round; at night the temperature often drops below freezing. The rainy season lasts from December to February, but during most of the year the high Altiplano plateau is parched and inhospitable. Around Lake Titicaca, rainfall is adequate, but there is less than 13 cm (5 in) a year in the extreme southwest. The fertile valleys in the Cordillera Oriental have a warmer, semiarid Mediterranean climate.