Abstract: Based on the atmospheric environment monitoring data of the China environmental monitoring station and the meteorological elements data of the National Climatic Data Center of the United States, this paper analyzed the spatio–temporal variation characteristics of air quality in the Yangtze River Delta urban agglomeration from 2015 to 2022. This study utilized stepwise regression and correlation analysis and established the correlation between ambient air quality and various meteorological factors. The changing trend of the influence of meteorological factors on ambient air quality was studied. The results showed that: (1) The air quality in the Yangtze River Delta urban agglomeration developed well during 2015–2022, and the annual rates of good air quality in Jiangsu, Shanghai, Anhui, and Zhejiang increased by 2.99%, 2.56%, 2.29%, and 1.96%, respectively. The monthly variation trend of the air quality index (AQI) in the Yangtze River Delta urban agglomeration was similar, with a high trend in winter (the average AQI was 90.1) and a low trend in summer (the average AQI was 39.7). (2) The meteorological factor with the most significant impact on air quality in the Yangtze River Delta urban agglomeration in summer is pressure (the correlation between pressure and AQI is 0.119 when there is pollution and 0.09 when there is no pollution). Further, the correlation between pressure and AQI increases at a rate of 6.71% and 0.58% per year when there is pollution and no pollution, respectively. (3) The meteorological factor with the greatest impact on the air quality in the Yangtze River Delta urban agglomeration in winter is wind speed (the correlation is −0.137 when there is no pollution; with pollution, the correlations were −0.120 and 0.249 before and after 2019, respectively). The correlation between wind speed and AQI increases at the rate of 3.72% and 0.39% per year when there is pollution and no pollution, respectively. These results indicate that the effects of pressure and wind speed on air quality in the Yangtze River Delta urban agglomeration continue to increase in summer and winter.