Flooding events are among the most costly and destructive events impacting a large number of populations worldwide. The magnitude and frequency of extreme flooding events are increasing every year due to climate change and urbanization. Accurate hydrologic modelling is vital for planning and applying flood control systems to reduce the impact of such extreme flooding events. Precipitation is an important primary input data used for developing hydrologic models, and the accuracy of precipitation data significantly impacts the model prediction accuracy. Point gauge observations have historically been the primary source of precipitation data for hydrologic models. However, precipitation obtained from the point gauge station does not capture the temporal and spatial variability of precipitation throughout the watershed. In this context, radar-based precipitation products have been commonly used as a replacement for gauging station data. Therefore, this study evaluates the performance of the Next Generation Weather Radar (NEXRAD) III precipitation product for hydrologic analysis. The Personal Computer Storm Water Management Model (PCSWMM) was used in this study for the generation and application of radar precipitation products for hydrologic research. This study proposed two watersheds of different scales (i.e., Ellerbe Creek watershed and River Des Peres watershed) to evaluate the performance of integrating NEXRAD III and PCSWMM for hydrologic analysis. The results revealed that the performance of radar precipitation product was superior in generating discharge hydrographs at watershed outlets compared to the precipitation data from the gauging station for the large watersheds. The discussions in this research will encourage researchers and system managers to improve current rainfall-runoff simulation models by application of radar precipitation products.