Temperature and precipitation data from 540 meteorological stations in China from 1961 to 2009, and the piecewise-linear fitting model (PLFIM) was used to analyze the changes in summer and winter temperature and precipitation at the interdecadal timescale. The Palmer drought severity index (PDSI) was chosen to examine the frequency of extreme droughts. Consequently, the interdecadal changes and spatial distribution characteristics of extreme droughts were analyzed for summer and winter. Furthermore, we considered the effect of temperature and precipitation on the occurrence probability of extreme droughts. The results suggest that from 1961 to 2009, extreme droughts were more frequent in northern China than in southern China during summer, whereas they were more frequent in eastern China than in western China during winter. After the last trend change, the occurrence probabilities of extreme summer and winter droughts increased. At the regional scale, the probability of extreme summer droughts increased in Northeast China, North China, and Northwest China, whereas the probability of extreme winter droughts significantly increased in Northeast China, North China, South China, and Southwest China. The analysis of the causes of the variations in the occurrence probabilities of extreme droughts showed that the precipitation change controlled the trend in the occurrence probability of extreme droughts before the 1990s. Subsequently, climate warming led to an increasing trend in the occurrence probability of extreme droughts, whereas the temperature and precipitation changes controlled the occurrence probability of extreme droughts over China.