This research uses the Soil and Water Assessment Tool (SWAT) model to determine if the model predicted output of Evapotranspiration (ET) varies when using different meteorological input data. The SWAT model integrated with ArcView will be used to test the varying methods of calculating ET and see if the output varies significantly between then local meteorological stations compared to the more general model-generated weather data. The overall goal of this research was to determine how sensitive the SWAT model was to the resolution of input meteorological data using the Alafia River drainage basin in West Central Florida. The initial input layers to SWAT were: Digital Elevation Models (DEMs), soils and landuse; then weather data from local stations were tested against model meteorology as well as the three calculation methods for ET (Penman-Monteith, Hargreaves and Priestley-Taylor). The output variable tested was ET out. Further, ET measurements that occur at a Florida Automated Weather Network (FAWN) site nearby were used as comparison to test the output of the model as well.