The East Asia summer monsoons bring moist, warm air to the region in the form of rain. This rainfall significantly effects China's economy and society. This is because it constitutes the bulk of the rain received by China in the course of a year. The East Asian summer and winter monsoons are among the primary factors determining China's climate.
Monsoon winds blow away from China and toward Africa during the winter. In summer, they move across the Indian Ocean and toward China. Approximately 70 percent of the annual rainfall in the Tian Shan Mountains falls as a result of the monsoons. In addition to the summer monsoon, the southwest monsoon, which primarily affects India, also affects the climate of China as far north as the Xinjiang province.
The monsoons affect more than China's annual rainfall. As they approach China from India, they must cross the Tibetan Plateau and Himalayan Mountains. When the warm, moist air of the monsoons hits the cold temperature of the mountains, it falls as rain on the Tibetan Plateau. Although this rainfall does not land directly on China, it is responsible for the yearly rising of China's Yellow and Yangtze Rivers. These rivers feed the coastal plain and provide water for much of China's agriculture.