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The Urban Heat Island (UHI) effect is a phenomenon that threatens life in cities nowadays. Among other strategies to adapt cities to this phenomenon is the use of the tempering potential of courtyards and changes in the albedo of the surfaces. However, there is little literature about the influence of the albedo on the thermal performance of the courtyard. This research aims to analyze the effect of albedo alteration of the surfaces of a courtyard located in Seville on its tempering potential and the comfort of the users. Besides, it evaluates the accuracy and suitability of the simulation tool ENVI-met, widely used for the simulation of outdoor spaces, by contrasting monitoring and simulation results. It is concluded that high reflectance surfaces reduce the surface temperature by reflecting solar radiation, so they accumulate less heat during daylight hours and release less heat at night, however, the high reflection compromises user comfort. Key Innovations• The use of ENVI-met has been validated to analyze the effect of surface albedo on a courtyard's performance. • Surface albedo has little influence on the air temperature of the courtyard, but it affects surface temperature, Mean Radiant Temperature, and user's comfort in a way that should be considered during the design of these spaces to balance the positive and negative effects. Practical ImplicationsFor ENVI-met simulations of courtyards, it is enough to model the part of the building surrounding the courtyard. High albedo is recommended for floor surfaces and medium-range albedo is recommended in walls, to balance the positive effect on temperatures and negative on comfort.