In the last years, climate change is exacerbating the presence and impacts of heatwaves. The sharp rise in temperatures and the consequent increase in temperature fluctuations pose risks to the population, the environment and society, but also impact on cultural heritage. This is true throughout the territory, but even more specifically in historic centers, which are characterized by a high density of assets and where high temperatures and morphological and construction characteristics can lead to the urban heat island effect, which amplifies the implications of heatwaves. However, the lack of high-resolution heat data limits the ability to monitor these phenomena and plan conservation and mitigation strategies. Therefore, this study proposes a useful method to map the spatial distribution of temperatures and temperature excursions in a city rich in cultural heritage, Matera (Italy) characterized by particularly fragile building materials, offering a useful tool for risk assessment and heritage management.