Crop water use and open water surface evaporation were estimated for a thirty eight year period, 1971‐2008, at 150 National Weather Service Cooperative Observation Network (NWS) stations throughout Utah and another 96 stations in adjacent states, within one degree latitude or longitude of Utah’s borders. The ASCE Standardized Reference Evapotranspiration Equation (Penman‐Monteith) was used to calculate tall crop reference evapotranspiration. Daily weatherdata (maximum and minimum air temperature and precipitation) from the 246 NWS stationswere provided by the Utah Climate Center.