China has a marked continental monsoonal climate characterized by great variety. Northerly winds prevail in winter, while southerly winds reign in summer. The four seasons are quite distinct. The rainy season coincides with the hot season. From September to April the following year, the dry and cold winter monsoons from Siberia and Mongolia in the north gradually become weak as they reach the southern part of the country, resulting in cold and dry winters and great differences in temperature. The summer monsoons last from April to September.
The warm and moist summer monsoons from the oceans bring abundant rainfall and high temperatures, with little difference in temperature between the south and the north. China's complex and varied climate results in a great variety of temperature belts, and dry and moist zones. In terms of temperature, the nation can be sectored from south to north into equatorial, tropical, sub-tropical, warm-temperate, temperate, and cold-temperate zones; in terms of moisture, it can be sectored from southeast to northwest into humid (32 percent of land area), semi-humid (15 percent), semi-arid (22 percent) and arid zones (31 percent).