The atmospheric circulation characteristics in the winter of 2021 (from December 2021 toFebruary 2022)are as follows. The polar vortex in the Northern Hemisphere is distributed in a multipoletype and the circulation shows a three-wave pattern in middle and high latitudes. The geopotential heightanomaly field at 500 hPa shows that the mid-latitude region of East Asia presents positive anomaly,theridge over Siberia is stronger,while the East Asian trough is weaker than that in normal years,so thecold air activity is less and its intensity is stronger. There are 8 gale processes (above 8-grade)overoffshore areas of China,among which 4 processes are influenced by cold air,three jointly by cold air andextratropical cyclones,and one jointly by cold air and tropical cyclone. There is no large-scale sea fogprocess in the coastal waters of China. There are two tropical cyclones generated over western NorthPacific and the South China Sea,and both of them develop into super typhoons. Among them,TyphoonRai (2021)is one of the two typhoons to reach the scale of super typhoon in the South China Sea inDecember in history. It is also the strongest tropical cyclone to hit the Nansha Islands directly in history and the latest super typhoon to affect the South China Sea. In addition,14 tropical cyclones are generatedin other sea areas around the world. There are 56 days with rough sea wave processes above 2.0 m overoffshore areas of China,accounting for about 62% of the total winter days. In winter,the sea surfacetemperature shows an obvious cooling trend in offshore areas of China,and the cooling amplitude of thenorthern sea areas is significantly greater than that of the southern sea areas. The sea surface temperaturein winter is generally higher than that of normal years.