Abstract:The main characteristics of the general atmospheric circulation in September 2020 are as follows. The polar vortex of Northern Hemisphere presented a single-pole pattern, while the westerlies presented a four-wave pattern in middle-high latitudes. The western Pacific subtropical high was distributed in the east-west direction, more eastward and southward than normal. The monthly mean precipitation amount was 88.1 mm, which is more than its normal value by 34.9%, being the most accumulated precipitation in the same period since 1961. The monthly mean temperature was 17.2℃, 0.6℃ higher than the climatological mean (16.6℃). The number of landing typhoons generated is less than normal, but Typhoons Maysak and Haishen brought severe gales and rainstorms to Northeast China, making the daily rainfall in many places exceeded the local historical maximum in September.