Deadly heat waves regularly strike Montreal’s vulnerable population. In its 2020–2030 climate plan, the City of Montreal aims to reduce the total area of surface intra-urban heat islands (SIUHI). The development of a characterization of vegetal and mineral surfaces is advocated for the evaluation of the territorial adaptation to heat waves. While the municipal administration recommends asset management in the rigorous planning of its infrastructures, this research proposes to model gray (street) and green (park) infrastructure assets from CIM information of a project, characterize them into vegetal and mineral surfaces, and monitor the temperature evolution of these surfaces through asset management. An IR thermal camera on board an airplane in 2016 and a drone in 2020 are used to monitor surface temperatures before and after construction of green and gray infrastructure. By establishing the classic vegetal surfaces (grass, plantation, tree) of a park as a reference, we validate to the municipal managers that the new retention surfaces at the time of their implementation, even mineral ones, do not create SIUHI. The approach makes it possible to consider the evaluation of the physical and thermal conditions of streets and parks as part of the activities of the assessment of municipal assets by taking advantage of CIM information.