Based on the observation data of daily precipitation and air temperature of 20 weather stations in Beijing Area from 1978 to 2012, the empirical relationship between precipitation and air temperature and the differences between urban and suburban areas in summer (June to August) were analyzed. The results showed that: (1) Daily precipitation presented a first increasing then decreasing trend with air temperature rising. For moderate and heavy rainfalls, precipitation kept stable and varied weakly with air temperature increasing after air temperature reached a threshold. While the air temperature rose further to a certain threshold value, precipitation decreased rapidly with air temperature rising. Before it reached the maximum value, the heavier the precipitation was, the closer the precipitation increase rate was to ClausiusClapeyron (CC) variability. (2) The critical values of precipitation frequency and intensity varying separately with air temperature variation were not the same. When air temperature was higher than the threshold, precipitation frequency and intensity also began to weak. The different magnitudes of precipitation varying with the air temperature had similar trends between the urban and suburban areas. However, precipitation increase rate before precipitation reached the maximum value was bigger in urban area than in the suburb, which indicated that precipitation in urban areas was more sensitive to temperature than that in suburbs.