Thermal Comfort is an important parameter in determining user satisfaction; the definition of the boundaries affecting comfort conditions allows energy conservation and helps in setting the standards. This study focused on investigating the thermal environment and its effect on the comfort mechanism in the hot arid climate of Cairo, Egypt. The results showed that the population of the study could bear higher indoor temperatures than that incorporated in the current model. The Adaptive Comfort Model and the detailed slopes of different climatic zones for different buildings were analyzed. An ANOVA test for different buildings'' neutral temperature across different climatic zones resulted in a significant difference which can be explained by the different climates, this led to the suggestion of a variable comfort model depending on different climate zones.