The main characteristics of the general atmospheric circulation in summer (from June to August) 2018 are as follows. The polar vortex was characterized by a monopole pattern in the Northern Hemisphere, which centered over the Arctic Ocean. The westerlies in middle and high latitudes presented a four-wave mode. Affected by the large-scale circulation, in June and July there were more tropical cyclone activities than perennial average in the southern sea areas of China and more sea fog activities in the northern sea areas of China. In July and August, the subtropical high lay more northward than ordinary yeas, therefore a remarkable number of typhoons hit East China. There were 18 typhoons nominated over western North Pacific and the South China Sea in this summer, which was 7 more than the previous average. Tropical cyclone activities are closely related with summer gale events and big waves in offshore areas of China. There were 20 gale events stronger than 8 grade this summer, including 13 produced by tropical cyclones (two processes accompanied with cold air activities), 5 by extratropical cyclones and quasi-stationary fronts, and two mainly by monsoon. There were 7 massive sea fog events over offshore areas in this summer, including 4 in June and three in July. Thirteen rough sea wave events above two meters occurred, including three in June, 5 in July, and 5 in August. There were 18 tropical cyclones over global oceans except western North Pacific, including 4 over the North Atlantic and 14 over the East Pacific.