Based on the daily maximum air temperature data from 74 stations in Hunan from 1961 to 2013, the complete time series of hot days is established. The temporal and spatial distribution and changing trend of hot days in Hunan during last 53 years are analyzed. The results show that hot days show an increasing trend with an increase rate of 2 days per 10 years, which is more obvious in the northern Hunan. The maximum hot duration shows a weak decreasing trend in the southern Hunan with a reducing rate of 0.5 days per 10 years, but there is a strong increasing trend in the north and central parts of Hunan with an increase rate of 1 day per 10 years. Since the 1990s, hot days in Hunan have increased and enhanced significantly. A climatic prediction model of hot days is established using the optimal subset regression method. The verification of the 53year historical records shows that the model can forecast hot days in Hunan satisfactorily, which can be put to operational use.