Accurate and reliable hydrological model outputs in river catchments is greatly improved by the inclusion of high-quality precipitation data, especially in areas with limited or nonexistent precipitation data. Assessing the accuracy of precipitation data is essential for accurate modeling of hydrological processes in watersheds, which is vital for efficient water resource management. This study aims to assess the accuracy of the Soil and Water Assessment Tool (SWAT) in predicting stream discharge in the Chemung River watershed. The process used both in-situ measurements and gridded reanalysis precipitation data from the National Oceanic and Atmospheric Administration (NOAA) and the National Centers for Environmental Prediction (NCEP). The efficacy of these precipitation products in accurately simulating stream discharge in the study area was assessed by comparing the projected values with the actual stream discharge using the Nash-Sutcliffe Efficiency (NSE) method. The findings indicated that the discharge was underestimated by NOAA's data (NSE, 0.25), although the gridded data yielded diverse outcomes. Nevertheless, when the NOAA data was combined with the gridded data, the model's performance was significantly enhanced, leading to an NSE value of 0.38. This suggests a more accurate SWAT model. Findings from this study are significant for enhancing hydrological predictions and water resource management in regions with limited precipitation data, offering a practical approach to enhancing model accuracy where data quality is a constraint.