The following are the main characteristics of the general atmospheric circulation in October 2013. There is one strong polar vortex center over the Northern Hemisphere. The circulation presents a four wave pattern in middle high latitudes. The meridional circulation is more obvious, the south branch trough and the West Pacific subtropical high are stronger than normal years. The monthly mean precipitation is 30.8 mm, 14% less than normal. The monthly mean temperature is 11.1℃, which is 0.8℃ lower than normal years. There are four cold air processes affecting China during this month. Typhoon Fitow makes landfall in southern part of East China and northern part of South China, bringing a severe rainfall process. The autumn drought across the central part of Jiangnan Region and Henan Province continues or develops. Besides, most parts of the central and eastern China suffers from fog and haze events.