In a scenario in which the climate changes subject urban centres and large cities to high levels of environmental vulnerability and criticality underway, it is evident the need to define operational and straightforward decision-making tools capable of prefiguring and verifying the effectiveness of urban transformation climate-adaptive regeneration processes. The Climate Adaptive Design Index for the Built Environment (CADI-BE) tool has been developed to assess the adaptive capacity and level of performance of open urban spaces to the stresses due to the increase in global average temperatures. The repercussions of these phenomena cause the occurrence of heatwaves and the urban heat island effect (UHI), bringing out the inability of cities to cope with changes in the climate, making urban open spaces unlivable and no longer the ideal habitat for everyday life and social interactions.