Climate change is a global reality, leading to consequences for both the natural and urban environment. These changes and their implications can be perceived in features such as ecological cycles, in the economic status of a country, or on the well-being and physical integrity of a population. Hence, this study aimed to analyse the effects of climate change on urban thermal comfort and the physiological limits of a population in a tropical city, applying the Physiological Equivalent Temperature (PET) index and correlating it to the local wet-bulb temperature. The method adopted consists of four stages: (1) assembling weather files for future scenarios; (2) setting up scenarios for computational simulations; (3) choosing the most adequate urban thermal comfort index; and (4) selecting a risk parameter to evaluate human health risk. The results show that the presumed urban temperatures, considering 2050 and 2080 scenarios as parameters, can cause serious damage to inhabitants’ health, given the frequency of high temperatures recorded in some months of the year. Accordingly, it is clear that there is a need for balance between the temperature variables and relative air humidity is required, striving for better comfort conditions, as well as improving users' permanence in external environments.