Because of the irregular terrain, the climate varies greatly from place to place. In the outer foothills adjoining the Indian plains, rainfall ranges from about 150 cm to 300 cm (60–120 in) a year; the forests are hot and steaming in the rainy season, while the higher hills are cold, wet, and misty. Violent Himalayan thunderstorms gave rise to Bhutan's Dzongkha name, Druk-Yul, which translates as "Land of the Thunder Dragon." Rainfall is moderate in the central belt of flat valleys (which have an elevation of 1,100–3,000 m/3,500–10,000 ft). The uplands and high valleys (above 3,700 m/12,000 ft) are relatively dry. There is less rainfall in eastern Bhutan. In general, the mountainous areas are cold most of the year. Temperatures there average 4° C (39° F ) in January and 17° C (63° F ) in July.