With an estimated population of around 6.2 million inhabitants, the Municipality of Rio de Janeiro (MRJ) faces significant challenges related to the rapid expansion of the urban area and increased exposure to disasters resulting from extreme climatic events. Exacerbated by local factors and specific characteristics of the Rio de Janeiro landscape, climate extremes behave heterogeneously in the analysed area, demonstrating how the ongoing and disparate urban expansion in the municipality exposes certain populations to more (or less) disasters caused by extreme temperature events. Phenomena such as urban heat islands (UHI), linked to a singular historical process of native vegetation suppression, soil impermeabilization, and increased use of materials with high heat absorption in the urban fabric, indicate a worrying trend, especially when associated with the growing incidence of cardiovascular diseases related to the impacts of extreme heat events, including persistent heatwaves. The analysis of the frequency and intensity of temperatures indicators observed in the municipality between 2015 and 2023 shows that the city (municipality) of Rio de Janeiro has experienced extreme heat events and significant deviations in average temperatures, indicating variations related to interactions between physical and socioeconomic factors specific to the geo-historical content of each Planning Area (AP). Discussing these phenomena and highlighting the existing spatial patterns underscores the urgency of strengthening public policies and implementing effective measures to mitigate and adapt the city to the negative impacts of extreme heat on human health and urban infrastructure, as well as increasing the municipality s resilience.