The main characteristics of the general atmospheric circulation in September 2018 are as follows.The polar vortex showed a dipole pattern.The circulation presented the distribution of a multiwave pattern in middlehigh latitudes.The northwestern Pacific subtropical high was weaker and remarkably more westward extended than normal.The monthly mean precipitation amount was 74.2 mm, which is 14% more than normal (65.3 mm). The monthly mean temperature was 16.7℃, 0.1℃ higher than normal. There were three largerange heavy rainfall processes over China, which happened in South China and the eastern part of Northwest China, causing serious disaster locally. Four tropical cyclones were generated over northwest Pacific Ocean and the South China Sea. Typhoon Mangkhut (1822) and Barijat (1823) landed in Guangdong Province. Moreover, Heilongjiang Province suffered from low temperature and freezing disaster. Autumn rain for West China came late, but heavy somewhat in Yunnan, southern part of Sichuan, Chongqing and Southern part of Guizhou.