The synchronously observed air temperature data from the new and old meteorology observation stations at Dongguan are analyzed with the difference method. The characteristics of high temperature weather since 1971 are discussed by means of the corrected observation data from the new station. In combination with the air temperature data observed from densely distributed automatic weather stations, the temporal and spatial patterns of high temperature weather from July to August in 2007 are further analyzed. The indexes for high temperature forecast and early warning are also discussed according to the temporal characteristics of meteorological data from the single weather station. The results show that the monthly mean maximum air temperature at old station was 0.83 ℃ higher than that at the new station, and the monthly extreme high air temperature at old station was also higher than that at new station. The number of high temperature days in summer was almost doubled every 10 years and there were 4 high temperature centers over Dongguan. The trend of air temperature profile curve from the single station can be used as a good indicator in high temperature forecasting and early warning.