The aim of this study is to comprehensively investigate the climatic factors affecting precipitation in the Urmia Lake basin during the 20-year period from 2003 to 2022. For this purpose, a set of satellite and reanalysis data including CHIRPS, MODIS, ERA5-Land, PM2.5 concentrations, and NAO and SOI teleconnection indices were used. The trend of the time series was assessed using the Mann-Kendall test and the age-slope estimator. The relationships between precipitation and climatic-environmental variables were examined using Spearman correlation, simultaneously and considering time lags (−3 to +3 months). Subsequently, the random forest model was used to identify the relative importance of the variables. The results showed that most climatic and surface variables, including precipitation, temperature, soil moisture, and NDVI, lacked a significant trend during the study period, while PM2.5 concentrations and SLP showed a significant increasing trend. Synoptic analysis of winter precipitation showed that the rainy years were accompanied by the weakening of the Siberian high pressure and the strengthening of the Mediterranean low pressure and troughs. The examination of time lags and correlations shows that soil moisture and relative humidity have the greatest relationship with precipitation and play a short-term precondition role in its occurrence. Based on the results of the random forest model, the soil moisture of the current month is the most important factor controlling precipitation. Overall, the findings show that precipitation plays an important role in surface–atmosphere processes. However, the long-term effects of lake drying and human interventions have weakened this relationship. As a result, the direct link between precipitation variability and both lake conditions and air quality has declined. Consequently, even in years with high rainfall, the drying trend of Lake Urmia has not been reversed.