Microclimate Modeling of UHI Mitigation Scenarios in a Historical Urban District

he study investigates the efficacy of various Urban Heat Island (UHI) mitigation measures within the UNESCO-listed historical center of Florence. Increasingly fre-quent and severe heatwaves during the summer season represent significant challeng-es for urban sustainability and public health in the outdoor urban environment. Using ENVI-met as simulation tool, the research assesses the current microclimate conditions of a district within a historical center and simulates alternative mitigation scenarios. It quantifies the benefits in terms of microclimate characteristics (Potential Air Temper-ature-Ta and Mean Radiant Temperature-MRT) and human comfort indexes (Physio-logical Equivalent Temperature-PET and Universal Thermal Climate Index-UTCI). The proposed interventions include blue and green infrastructures as well as shading sys-tems installed across the district. Current climate conditions are characterized by an average Ta of approximately 32°C and MRT exceeding 59°C; consequently, the ana-lyzed area falls into the very strong heat stress category for both the calculated com-fort indexes. All evaluated mitigation measures result in improving microclimate con-ditions as well as enhancing human thermal wellbeing within the outdoor environ-ment. The most effective district-level intervention is the installation of shading fab-rics, which reduces average Ta by 0.2°C and MRT by up to 14°C compared to the cur-rent scenario. Interventions tailored for the main square significantly reduce both UTCI and PET values, shifting the thermal stress from very strong to strong or even moderate. These findings highlight the potential of localized and tailored interventions to successfully integrate climate mitigation strategies within sensitive historic urban districts.