Abstract—This paper describes a methodology for the evaluation of the distribution networks resilience in large metropolitan areas during heat waves. These weather conditions (very hot and dry periods) in recent years have become more and more frequent due to climate changes. Thus, procedures to evaluate their impact on electricity networks assumed a particular interest. In the paper, a novel approach for the modeling of heat waves is presented and an example is provided based on a simple network in order to better highlight how the procedure works, the results obtained and the methodology potentials. A combination of three in-cascade models is used to evaluate the fault risk of each network component: a thermal, an aging and a reliability model. On the basis of the work described in this paper, a software tool has been implemented, used by the Italian DSO Areti SpA for evaluating the resilience of the distribution system of the Italian capital of Rome.