Abstract:The main characteristics of the general atmospheric circulation over the Northern Hemisphere in October 2020 are as follows. The polar vortex showed a dipole pattern with intensity similar to climatic state. The western Pacific subtropical high broke into two rings near 130°E. As a whole, the subtropical high was stronger than normal, and the location of its east ring was noticeably more eastward and northward than normal. During the month, the subtropical high experienced weakening with retreating to the east and then moving westward again. The October monthly mean precipitation in China was 30.1 mm, less than the normal by 16%. The monthly average temperature of China was 10.4℃, roughly equivalent to climatic state. There were four nationwide cold air processes with moderate strengths in this month, of which the strong cold air event during 20-23 caused blowing sand. Two torrential rain processes occurred in October, one was triggered by shear line with cold air and the other by typhoon. There were seven typhoons generated in the western North Pacific and the South China Sea in this month, 3.3 more than average numbers. One of the seven typhoons made a landfall. In addition, one haze-fog process was seen in October, and the autumn rainfall in western China was more than normal, lasting a longer time.