The main characteristics of the atmospheric circulation in the winter ( from December to February ) of 2020 are as follows. The polar vortex is characterized by the dipole type in the Northern Hemisphere and three-wave mode in middle and high latitudes, and the trough and ridge in the westerlies are significantly stronger than those in normal years . The geopotential height anomaly field shows that the mid-latitude region of East Asia is in a negative anomaly area, the cold air is stronger, and the gale process is significantly increased due to the strong East Asia major trough. There are 11 gale processes ( above 8-grade ) in inshore, including 7 processes influenced by cold air, 2 processes influenced by cold air and passing cyclone over seas, 1 process influenced by cold air and tropical cyclone and 1 process influenced by extratropical cyclone. There are 4 large-scale sea fog processes in the coastal waters and sea fog mainly appears in Bohai Sea, Bohai Strait , the northern and central Yellow Sea, Qiongzhou Strait and Beibu Gulf mostly from night to early morning. Two tropical cyclones are generated over the Northwestern Pacific and the South China Sea. In addition, 16 tropical cyclones are generated over the world’s other oceans. There are 54 days with rough sea wave processes above 2 m over offshore areas of China accounting for about 60% of the total days of winter. The sea surface temperature difference in winter from north to south increased from 23℃ in December 2020 to 27℃ in February 2021.