Using the daily meteorological drought index, daily precipitation and Hunan weather/climate regionalization data of 97 meteorological stations in Hunan, the extreme drought characteristics of Hunan and the potential of weather modification during extreme drought periods are studied. The results show: Hunan has considerable potential for rainfall enhancement during the extreme drought periods. The extreme drought frequency and the interdecadal variation of atmospheric precipitation in each subarea are characterized by the characteristic of less in North and greater South. The annual number of days in which rainfall may be enhanced in each area during extreme drought periods is mainly characterized by monthly differences, which is mainly concentrated from August to October. The small difference in each partition area and the number of rainincreasing days in each period in the drought period is about 16% to 20% of the drought periods. There are 11 types of extreme droughts in Hunan according to the occurrence season. The summerautumn continuous droughts have the highest occurrence frequency, which have the highest number of days in which rainfall may be enhanced.