Abstract:Meteorological conditions may have a great impact on PM2.5 pollution during the heavy haze winter in Chinese cities. Here, we examined the effects of meteorological factors on PM2.5 concentrations from December 2013 to February 2014, and from December 2014 to February 2015, in five cities—Shijiazhuang, Xi'an, Beijing, Taiyuan, and Guangzhou exhibiting different levels of PM2.5. We found (1) meteorological factors affected daily PM2.5 concentrations, and variables differed in cities with varied pollution levels. Significant positive correlations were obtained between humidity and PM2.5 concentrations in Shijiazhuang, and a significant negative correlation was also obtained for wind speed. Significant positive correlations were obtained between humidity and PM2.5 concentrations in Xi'an, and a significant negative correlation was found for wind speed. Significant positive correlations were obtained between humidity/temperature/minimum temperature and PM2.5 concentrations in Beijing, and a significant negative correlation was found for wind speed. Significant positive correlations were obtained between humidity/temperature/minimum temperature/maximum temperature and PM2.5 concentrations in Taiyuan, and a negative correlation was found for the maximum sustained wind speed. Significant positive correlations were obtained between humidity/maximum temperature/precipitation and PM2.5 concentrations in Guangzhou, and a significant negative correlation was found for wind speed. (2) Meteorological factors can explain the smaller variability in PM2.5 concentration in cities that have heavier PM2.5 pollution. Shijiazhuang, which represented a severely polluted area, showed meteorological factors of 0.27 after multiple regression analysis (R2). Xi'an, which represents a heavy polluted area, showed meteorological factors of 0.29 (R2). Beijing, which represents a moderately polluted area, showed meteorological factors of 0.46 (R2). Taiyuan, which represents a polluted area, showed meteorological factors of 0.67 (R2). The results provide a scientific basis for regional ecological environment planning and coordinated urban development. Therefore, understanding the main meteorological factors and their impact on urban PM2.5 in different cities provides a theoretical reference for air pollution control and improvement of prediction accuracy.