Conditions of the thermal environment in outdoor spaces determine not only its quality, but also the risk of morbidity from remaining in it. The objective of this research was to estimate the effect of dry bulb temperature and relative humidity on the perceived thermal sensation in outdoor spaces in hot dry climate. The thermal comfort adaptation approach was used with the thermal sensation interval means method, the analysis considered three activity levels for the warm period (with 823 observations) and cold period (with 863 observations), and the adaptation level of subjects based on their thermal sensation. The results indicate that even when the critical effect is due to the dry bulb temperature, the relative humidity has an important effect on the perceived sensation.