The Urban Heat Island (UHI) phenomenon presents significant challenges for urban environments, with thermal stress leading to discomfort and potential health issues for residents. Italian urban centres are particularly exposed to outdoor overheating conditions and summer heat waves, also due to the ongoing increase in external temperatures. The available mappings of UHIs are based on zoning from satellite data with broad meshes that do not allow detailed analysis at the local scale. Building upon these, the research aims to evaluate microclimatic conditions within an urban district in Florence, to precisely identify areas susceptible to discomfort. Using an urban district modelling workflow based on Grasshopper plugins for environmental analysis (Ladybug, Honeybee, Dragonfly), the study accurately replicates the volumetric and physical characteristics of buildings within the area of interest and evaluates their impact on the local microclimate through dedicated simulations. Climate data available at the urban scale are processed in relation to the specific characteristics of the site under examination to obtain data relevant to local conditions. The research delves into two distinct sections of the district under study, including a road intersection area and a continuous road segment. The results highlight the presence of areas where individuals may be exposed to thermal stress conditions ranging from moderate to severe, particularly significant in unshaded portions where the mitigating action of winds is insufficient. By pinpointing in detail, the areas most susceptible to overheating phenomena, the results allow for the precise identification of interventions aimed at alleviating discomfort and improving urban liveability. In this perspective, the study represents the initial phase of a broader research endeavour, laying the groundwork for the development of mitigation strategies tailored to the specific needs of the urban environment considered.