Abstract:Using 12 hourly station rain gauge data at 588 stations during 1969-2008, this paper analyzes the spatial characteristics and seasonal variation of rainfall durations over China. The result shows that in south of 35°N, the annual mean averaged rainfall duration over eastern and western regions is longer than that over the middle region, while over north of 35°N, northwestern China and the west of Inner Mongol, the averaged rainfall duration is the shortest all over China, and the rainfall duration over the north of northeastern China is longer. According to the duration time, precipitation events are classified. Over the three regions of eastern China (southeastern China, the region of Jianghuai and Huanghuai, and the region of northeastern China and the north of North China), the percentages of the short duration rainfall (1 time duration for 12 h) to the total rainfall gradually increase during the whole year for both amount and frequency, while those of long duration rainfall (no less than 3 times duration) decrease. The seasonal variation of averaged rainfall duration in China reasonably reflects the spring persistent rain over southeastern China, the Meiyu, the summer rainy season over northeastern China and the north of North China, the autumn rain over Guanzhong Basin and Hanshui River Valley and the summer rain over the Tibetan Plateau and southwestern China. The averaged rainfall duration is long in autumn and winter over southeastern China, in the first dekad of October over Jianghuai and Huanghuai region and in the last dekad of October over southwestern China, which is not in accordance with the variation of rainfall. These features can be attributed to the increasing frequency of the long duration rainfall and decreasing frequency of the short duration rainfall. Subseasonal variation of averaged rainfall duration over the three regions of eastern China corresponds to the ‘northward advance and the southward retreat’ of the monsoon rain belt.