Abstract: In order to discuss the influence of different air temperature indices on summer electrical energy supply in Tianjin, the relationships of the daily electrical energy supply, daily peak load, daily minimal load with seven air temperature indices (two o’clock, eight o’clock, fourteen o’clock, twenty o’clock, daily average, daily maximum and daily minimum air temperature) were analyzed by statistical methods, and the hypothesis test of the correlation coefficient had been done. The results indicate that the correlations of the average air temperature with daily electrical energy supply and daily peak load are significant, and the correlation between two o’clock air temperature and the daily minimal load is significant. The daily average temperature and two o’clock air temperature are the main meteorological elements influencing the urban electrical energy supply in summer.