The main characteristics of the general atmospheric circulation in summer 2021 (from June to August) are as follows. The polar vortex is characterized by a monopole pattern in the Northern Hemisphere, centers in the Arctic Circle toward the Western Hemisphere, and is stronger than average. East Asia is dominated by zonal circulation, and the subtropical high lies slightly more westward and southward than average. In June, the temperature in the northern sea area is low, leading to frequent sea fog processes over Bohai Sea and Yellow Sea. In July, the southwest monsoon advances and tropical cyclones are active. In August, the subtropical high strengthens and extends to the west, resulting in less tropical cyclone activity. There are seven sea fog processes over offshore areas in summer, including four in June and three in July. There are nine gale processes above 8-grade over offshore areas of China, among which six are related to tropical cyclones and three are influenced by extratropical cyclones entering the sea. There are 10 rough sea wave processes above two meters, and the total number of days is 38 d. The sea surface temperature increase profoundly in the northern and eastern seas of China, which reduces the sea surface temperature north-south gradient. There have been 9 typhoons over the western North Pacific and the South China Sea, among which Typhoon In-fa causes a large-scope, long-lasting, and intense gale process over the offshore.