Recent critical events brought attention to the increasing exposure of urban environments to both slow and rapid onset disasters, which arise from both anthropogenic and natural causes. These events have particularly severe effects on historic centres, which are characterized by high levels of vulnerability and valuable assets exposed to risk. To minimize the impact on tangible and intangible cultural heritage values, especially in outdoor public areas such as squares and streets, it is crucial to establish coherent mitigative and adaptive solutions for different types of hazards. This research presents a methodology aimed at defining levels of multi-vulnerabilities in historic districts in the Apulia Region (Italy), considering the recurrent hazards to which the latter is prone. It uses a multi-step process based on structured and non-structured methodologies and tools for single risks, examined in combination, to determine the main properties characterizing the vulnerability assessment. The dataset was analyzed in a GIS environment to evaluate the selected Apulian case study (Molfetta) in Multi-Asynchronous Hazard scenarios, showing the compounded levels of criticalities for open areas and streets. This information is intended to support authority and emergency managers in identifying priority interventions and increasing the resilience of the outdoor public places.