Abstract: Using the daily meteorological observation data of Chongqing from 1961 to 2021, the weekly changes of the average temperature and precipitation frequency in Chongqing were objectively and quantitatively analyzed. It is found that the temperature consistently shows a negative weekend effect, that is, the temperature on the weekends is lower than that on the working days, the peak value appears on Wednesdays and the valley value appears on the weekends. The frequency of precipitation is opposite to the temperature, most areas show a positive weekend effect, that is, the frequency of weekend precipitation is higher than that of working days, the valley value appears on Wednesdays and the peak value appears on the weekends. From the perspective of aerosol effect, the concentration of aerosols on weekends is less than that on weekdays, which is conducive to the temperature being lower on weekends than that on weekdays. The aerosol concentration is greater on weekdays than that on weekends, due to the second indirect effect of aerosols, the radiation forcing caused by the increase of man-made aerosols suppresses precipitation, which is conducive to the precipitation being less on weekdays than that on weekends. From the perspective of urbanization process, with the acceleration of urbanization process, the difference in the impact of human activities on urban climate on weekdays and weekends is expanding, which is conducive to the more significant difference in temperature and precipitation on weekdays and weekends, and intensifies the weekend effect of the climate in Chongqing.