Brasília was originally conceived as a car-oriented city, designed for 500,000 inhabitants in the 1960s. However, its population has now reached approximately 3,000,000, which has led to continuous urban expansion. This rapid growth has driven significant transformations in urban infrastructure and building design, characterized by increased asphalt paving and widespread use of reflective façade materials replacing traditional brises-soleil. The South Commercial Sector (SCS) is undergoing revitalization, modernizing building façades and expanding asphalted areas, reducing urban permeability. This study examines the impacts of these changes on the urban microclimate, particularly pedestrian thermal comfort, assessed using the Mean Radiant Temperature. Block 01 of the SCS was selected for analysis due to its representative urban characteristics. Simulations were conducted under four conditions: the current state, modified building façade materials, increased impermeable ground-level areas, and a combination of both. Using ENVI-met v.5.7.1, along with Leonardo plugin, the study generated maps illustrating mean radiant temperature. The findings indicate that extensive soil impermeabilization negatively impacts the thermal comfort of public spaces during hot periods. Surprisingly, this study reveals that replacing current façades with reflective glass results in lower minimum nocturnal mean radiant temperatures, diverging from previous studies. This research underscores the critical role of façade and ground material selection in shaping microclimatic conditions and pedestrian comfort.