This study selected 62 meteorological stations in the southwest area of Taiwan-including Tainan, Kaohsiung and Pingtung counties. The daily rainfall data from 1999 to 2002 was obtained for analysis of rainfall distribution and characteristics. According to differing meteorological phenomenon, the four types of characteristics of rainfall distribution in the southwest area of Taiwan can be summarized as follows: (1) Frontal rain occurred from autumn to spring. The geographical difference of rainfall shows more homogeneously than other types. But during the Mei-yu (Chinese)/Baiu (Japanese)/Plum (English) rainy season, from May to June, clear geographical differences appear. (2) Convectional rain always accompanied thunder, known as thunder storm, and occurred in the summer season. This was more prevalent in the mountain areas than on level land. (3) 80% of typhoon rain occurred during the summer season. Its geographical distribution, as closely tracked by a typhoon tracking system, showed the rainfall in mountain areas to be heavier than on level land. (4) Topographical rain occurred in the southwest directional of mountain areas. This was almost direct proportional to annual rainfall distribution.