Chongqing is locates in the subtropical climate zone, between the Qinghai-Tibet Plateau and the Middle-lower Yangtze Plain. It belongs to the humid sub-tropical monsoon climate belt. Its annual average temperature is 18 C (64 F) to 20 C (68 F) , with a low temperature of 4 C (39 F) in winter and a high temperature of 40 C (104 F) in summer. Chongqing is famous for its hot summer and it is well known as one of 'the three furnace cities' in China. In the seasons of spring and summer, it often rains at night, so Chongqing gets the reputation of "Ba Mountains' Night Rain". Furthermore, in the winter and spring, most days in Chongqing are foggy and it is also called "foggy city".