Abstract: In order to analyze the relationship between the summer electric daily peak load and meteorological factors, weather sensitive load, which is influenced by weather conditions, is isolated from the load database. Based on the consideration of cumulative effect of weather sensitive load caused by meteorological factors, relationship model between change rate of weather sensitive load and meteorological factors is built. Then the grey incidence between summer weather sensitive load for a city from 2004 to 2005 and temperature\|humidity index, daily mean temperature and daily highest temperature are analyzed. The results show that temperature\|humidity index is the biggest relation variable that influence summer weather sensitive load. On this basis, a three\|multinomial model of summer weather sensitive load and temperature\|humidity index is established and the relation between temperature\|humidity index and the change rate of meteorological load is also calculated. The work in this paper is reference to the load forecasting and dispatching.