Abstract:Based on daily meteorological observational data of frost in China, the spatiotemporal distribution of frost has been investigated from 1957 to 2006. The climatic change of frost season, the first and last dates of frost are mainly analyzed. The results show that the frost seasonal length is longer in the north and on the mountain than in the south and on the plain in China as a whole. The longer frost season is always consistent with the earlier first frost day and the later last frost day, vice versa. In the background of global warming in the last 50 years, the frost seasonal length shortened, the first dates of frost occurred later and the last dates of frost occurred earlier, especially after 1990s. The notable trend is evident in Northeast China, North China, Middle Inner Mongolian, Yangtze-Huaihe region as well as Yunnan-Guizhou Plateau and some part of South China, while no obvious trend is found in Sichuan Basin and the mid-lower Yangtze River Basin, even a slightly reverse trend is showed in those places. Comparing with the trend of the first frost date and the last frost date, the latter appears to have a marked change than the former, which may have a very close relationship with the different variation of seasonal temperature.