Abstract

The aim of this study was to assess the evolution of registered air temperatures in the town of Caicó, Rio Grande do Norte, Brazil, over a fifteen-year period (from 1996 to 2010), analysing the heat susceptibility of the local inhabitants through the human comfort indices for the same period. In order to discuss the relationship between the temperatures and the issue of human thermal comfort in Caicó, three indices of human thermal comfort were applied: Discomfort Index (DI), the Effective Temperature taking wind velocity (ETv), and the Universal Thermal Climate Index (UTCI). We found that in Caicó the air temperature is naturally very high, with daily means circa 30°C, maximum temperatures ~35°C and minimum temperatures around 24°C, putting Caicó at the limit of the human comfort zone almost year round. Even though temperature changes were not detected in the studied fifteen-year period, the thermal indices show us that Caicó experienced thermal stress due to heat each of the studied years(1996–2010), and it is only in the winter time—in July, August, and September—that Caicó has no thermal stress. We also verified a lack of compatibility between the construction materials used in the buildings, urban forestry, and the town’s climatic reality in Caicó city. This situation could be exacerbated in the future if air temperatures rise due to global warming, bringing risks to the local inhabitants.