Climate change impacts such as extreme events and progressive global warming are threatening the conservation and liveability of urban cultural heritage. Understanding climate risks on heritage should be part of policy and planning decision-making processes to increase resilience and sustainability of both social and built environmental systems. However, despite a large body of literature focusing on climate-related hazards, there is a noticeable knowledge gap regarding a holistic conceptualization of the risks in historic urban areas, which is particularly noticeable in the case of the impacts of heat waves and heat urban island phenomena on urban heritage.The scope of this thesis is to assess the impact and intrinsic characteristics of the area to determine risk, which serves as the basis for future prioritization of climate change adaptation interventions. The thesis develops a methodological approach for vulnerability and risk assessment supported by a multi-scale urban model that represents the interaction between urban spaces and heat waves via Geographic Information Systems (GIS) data. The methodology delivers a robust and replicable tool by using a categorization method for urban modelling that considers the vulnerability of historic areas both as urbansystems and as heritage areas.The MIVES (Integrated Value Model for Sustainability Assessment) methodology was applied, in order to provide decision-making with objective and justified prioritization. To frame a holistic approach, socio-economic, cultural, governance (services and resources) and physical (gathering tangible characteristics of all infrastructures, elements and buildings) aspects of the system are taken into account. The methodology is tested for its replicability in two case studies, the historic area of Bilbao, Basque Country, and the old quarters of Naples, Italy.