Abstract:The main characteristics of the general atmospheric circulation in September 2019 are as follows. The polar vortex of Northern Hemisphere presented a single-pole pattern. In the mid-high latitudes of Asia, the circulation presented a two-trough pattern. The Northwest Pacific subtropical high was more westward and stronger than normal. The monthly mean precipitation amount is 62.4 mm, which is less than its normal value (65.3 m) by 4%. The monthly mean temperature is 17.7℃, 1.1℃ higher than its climatological mean (16.6℃). Four regional torrential rainfall processes occurred in China during September, and two of them were caused by tropical cyclones. In September, six tropical cyclones were generated over the Northwest Pacific and the South China Sea, no one landing China. Moreover, the autumn rain of West China started earlier than normal in the southern area and had a significant impact. Meteorological drought developed continuously over the lower-middle reaches of the Yangtze River. High air temperatures appeared over South to Yangtze River, South China and parts of North China. Heilongjiang, Inner Mongolia and many other regions were attacked by hail, and some areas of the two provinces suffered from low temperature and freezing disasters.