The following are the main characteristics of the general atmospheric circulation in September 2012. The polar center over the Northern Hemisphere is a single vortex pattern and deviated to the Western Hemisphere. The circulation presents a five wave pattern in the middle high latitudes and the trough areas are over the east part of Asia, the west part of Asia, the middle part of the Pacific, the east part of North America and the west part of Europe, respectively. The intensity of the subtropical high is slightly stronger than normal years, and its western ridge spot has large variation during September. The monthly mean temperature (16.6℃) is nearly the same as the value of normal years. The mean precipitation (73.8 mm) is 13.2% more than normal (65.2 mm). There are six precipitation processes and three tropical cyclones generated in the western North Pacific with none landed in China. In this month, freezing calamity occurred in several northern provinces of China and sixteen provinces (regions, cities) suffered from strong wind and hail disasters.