The main characteristics of the general atmospheric circulation in December 2021 are as follows. There were two polar vortex centers in the Northern Hemisphere. The East Asian major trough was strong and westward. The northwestern Pacific subtropical high was close to the normal situation. The monthly mean precipitation amount was 8.7 mm, which is 17.1% less than normal (10.5 mm). The monthly mean temperature was -2.3℃, which is 0.9℃ higher than normal (-3.2℃). There were three nationwide cold wave processes and one large-scale fog-haze processe in this month. In addition, Super Typhoon Rai slammed head-on into the Spratly Islands.