Modelling the Outdoor Thermal Benefit of Urban Trees: A Case Study in Lecce, Italy

Urban vegetation plays a key role in mitigating thermal stress in cities, particularly in Mediterranean climates increasingly affected by urban heat. This study evaluates the impact of vegetation on outdoor thermal comfort in Piazzetta San Michele Arcangelo, a square in Lecce (Southern Italy), using the ENVI-met microclimate model. Two scenarios were simulated: the current configuration and a hypothetical one without trees. Results show that vegetation reduces air temperature during the hottest hours (up to −0.52 °C on average) and improves thermal comfort, as indicated by the Universal Thermal Climate Index (UTCI), with reductions in “very strong heat stress” up to 43% at peak times. At night, tree canopies limit radiative cooling, leading to slight temperature increases. The findings confirm the crucial role of urban greening in enhancing outdoor thermal comfort and provide quantitative support for sustainable urban planning strategies in Mediterranean contexts.