Using a distributed hydrological model, this study investigated the influence of spatiotemporal ResolutionResolution of precipitation data on simulating flood peak discharge in the Ramos River Basin. Various precipitation datasets with spatial resolutions (0.25 km to 10 km) and temporal resolutions (1 hour to 48 hours) were evaluated. Results showed that finer resolutions generally provided more accurate predictions of flood peak discharge. The model calibrated with a 0.1 km spatial resolution precipitation data achieved an RMSE of 100.123 m3/s, NSE of 0.789, and R2 of 0.901, indicating good performance. In contrast, coarser 5 km and 10 km resolutions had much higher errors (RMSE 500.567 m3/s and 600.678 m3/s, respectively) and lower goodness of fit. The findings underscore the importance of spatial Resolution in hydrological modelling for reliable flood forecasting to support water resource management and disaster risk reduction strategies. However, computational constraints and data quality issues must be addressed to enhance model reliability further.