With a concept intiated by American bio-meteorologist R. G. Steadman, the monthly mean apparent temperatures at 14p·m. in summer (Juno to Aug.) in China are calculated, and the effects of wind and air humidity on the apparent temperature are discussed. The synoptic, and climatic features of the sweltering hot in summer in the reaches of the Changjiang River and in South China are compared by analysis of the day to day apparent temperatures in the two regions.