<Abstrcat>The hydrology and aerography indexes change in the middle of the rainy season in dry-hot valley are explored in this paper, which involves the mean ground temperature, relative humidity, runoff on trunk, rainfall, evaporation quantity, etc.

The major rainy seasons in whole China are firstly defined using the climatic pentad rainfall amounts datasets of 740 stations,and then the climatic characteristics of the rainy season,including the major rainy season,the spring and autumn rainy seasons,are discussed.

Based on the history data during 30 years in shiping, set up a pattern of more intersecting and interrelated factors for forecasting the beginning date of flood season.