The climate in Georgia and other southeastern states of the USA is considered to be humid and usually the annual precipitation is greater than the annual evapotranspiration (ET). However, in some months supplemental irrigation is needed to prevent yield reducing water stress due to the temporal rain variability and sometimes due to droughts. The Priestley-Taylor (1972) (PT) equation has been operationally used in Georgia to compute ET for irrigation scheduling because of its simplicity, its general acceptable performance in humid regions, and its limited input requirements. A recent study for a site in the humid southeastern US found that PT overestimated ET and that FAO 56 Penman-Monteith (PM) was more accurate. The goal of this study was to reconsider the use of PT and to replace it with FAO56-PM, especially because of the availability of more than 60 weather stations across the state as part of the Georgia Automated Environmental Monitoring Network. Nine representative sites, including Blairsville in a mountainous area and Savannah in a coastal area, were selected to assess the potential improvements that may be achieved by replacing PT with FAO56-PM. Each site had at least 10 years of daily records that included minimum and maximum air temperature, solar radiation, wind speed and vapor pressure deficit. The absolute difference between annual ET of PT and FAO56-PM was less than 50 mm for six sites, about 80 mm for two sites, i.e., Blairsville and Rome, and 161 mm for Savannah. For many sites PT underestimated ET during the winter and overestimated ET during the summer, with the highest overestimation occurring in Savannah and Blairsville. Based on these results it is anticipated that the use of FAO56-PM for estimating ET would improve the irrigation efficiency in Georgia, especially for the mountainous and coastal areas.