The following are the main characteristics of the general circulation of atmosphere in May 2010. There are two polar vortex centers in the Northern Hemisphere. The circulation presents a fivewave pattern in middlehigh latitudes. The intensity of three major deep troughs are weaker than their average conditions. The subtropical high shows a belt figure. The western ridge spot of the high extends to the Indian Ocean. The monthly mean temperature (16.0 ℃) is 0.4 ℃ higher than the same period of normal years and the national mean precipitation (80.1mm) is 13.4 mm more than the same period of normal years. There are three cold air processes and three sand and dust processes in the month.