Data scarcity has been a huge problem in modeling the water resources of the Upper Blue Nile basin, Ethiopia. Application and evaluation of performances satellite rainfall estimates (SRE) for representing the special and temporal variability of rainfall in data poor catchments such as Guder, Main Beles and Anjeni watersheds are vital. Satellite data and different statistical methods have been used to improve the quality of conventional meteorological data. This study assesses the applicability of the Multi-source Weight Ensemble Precipitation (MSWEP) and Tropical Rainfall Measuring Mission (TRMM) climate data in modeling the hydrology of the region. The Soil and Water Assessment Tool was set up to compare the performance of MSWEP and TRMM (3B42RT) weather with that of conventional weather in simulating observed stream flow at three river gauging stations in the Upper Blue Nile basin. The simulation using calibration the observed station weather data performed satisfactory (0.5<NSE ≤ 0.65) and PBIAS ( ). The bias Corrected TRMM and MSWEP weather data also performed reasonably for the three watersheds with the Nash Sutcliffe efficiency and coefficient of determination of NS (0.55, 0.61,0.45 and 0.55, 0.64, 0.51) and R2 (0.70, 0.69, 0.52 and 0.71, 0.72, 0.57) for Guder, Main Beles and Anjeni respectively. Overall the simulation with the observed weather performed better than the Satellite weather. However, in data-scarce regions such as many parts of the Upper Blue Nile basin, TRMM and MSWEP weather could be a valuable option for hydrological predictions where observed gauges are not available.