Electrical load is significantly impacted by weather conditions. Therefore, the seasonal variation, holiday effects, weekend effects, and the weather dependency of daily maximum electrical load are investigated by using the daily maximum electrical load data in Shanghai and meteorological observations from the Xujiahui weather station from May 2010 to December 2013. The stepwise regression method and filter technique are employed to build the meteorological forecast model in winter and summer. The model consists of two components: regular change component and weathersensitive component. The results show that the effects of various holidays are different. The Spring Festival has the longest and greatest influence on daily maximum power load. The holiday effect is more pronounced during the first several days of the National Day than in the other days. The weekend effect is greater in summer than in other seasons. The best model is able to explain most of variability in daily maximum electrical load, with the mean prediction relative error less than 5%.