The following are the main characteristics of the general circulation of atmosphere in April 2013. There is one polar vortex center in the Northern Hemisphere, and the strength is similar to normal years. The circulation presents a four wave pattern in middle high latitudes. Both of the south branch trough and the Northwestern Pacific subtropical high (NPSH) are slightly weaker, unfavourable for the drought relief in southwestern China. The monthly mean temperature is 11.0℃, equal to the value in the normal years except the unusual low temperature in northeast. The average precipitation of China is 43.2 mm, 1.5 mm less than the normal. There are 2 cold surge processes accompanied by sand dust events in April. The southern part of China has 3 severe precipitation events, of which the process in 29-30 April covers the largest area and has the strongest intensity, especially in South China and Jiangnan region, severe convections happen at the same time.