We evaluated human comfort in different urban sites to illustrate the use of OUTCOMES (OUTdoor COMfort Expert System), a Windows® program that was designed with the goal of providing an easily used human comfort evaluation tool that includes tree and urban structural influences on thermal comfort. The program produces an index of comfort for a person based on an energy budget calculation derived from the COMFA model of Brown and Gillespie (Microclimatic Landscape Design, John Wiley, 1995). The energy budget is based on solar radiation inputs, air temperature, humidity, wind speed, reflectivity of the ground and nearby objects, sky view, clothing, and activity of the person. To include tree influences on solar radiation, OUTCOMES includes a graphical tool that provides an elevation (side) view of a tree and a plan (top) view of the tree crown outline and its shadow to show users whether a person would be shaded at the designated time. In OUTCOMES, users enter weather data and run the program for one design date and time with each run. Users can choose from among 46 tree species with representative crown transmissivities in estimating the amount of solar radiation on a shaded person. Another program developed for testing the energy budget algorithms in OUTCOMES accepts Typical Meteorological Year (TMY) data to calculate in one run the human energy budget for one site for many hours of typical weather data, even for all the hours in a year, though differences in shading through a day are not automatically included. An analysis using the energy budget model for three sites with meteorological measurements during the month of August in Atlanta, Georgia, showed that a downtown site with a sky view factor of 0.67 was comfortable only 55% of the time, whereas a forested site in a botanical garden with a view factor of 0.23 was comfortable 77% of the time, and a backyard residential site with a sky view of 0.26 percent was comfortable 71% of the time.