Assessing intra-urban thermo-hygrometric variability and thermal comfort through an observational network in a Mediterranean city

Urban morphology strongly influences the spatial distribution of temperature, humidity, and thermal comfort within cities, generating significant intra-urban climatic variability. This study investigates the relationship between urban form and local microclimatic conditions in Lecce, a medium-sized Mediterranean city in southern Italy.

The analysis was conducted during the summer months (June–August) of the two-year period 2024–2025. A monitoring network consisting of ten sensors distributed across urban and suburban environments was used to collect air temperature (°C) and relative humidity (%) data. The sensors were installed in different urban settings and at different heights, ranging from street canyons to rooftop locations, allowing for the characterization of thermo-hygrometric variability across the city. Thermal comfort conditions were also assessed using the Heat Stress (HS) index.

The statistical significance of intra-urban differences was evaluated through repeated measures ANOVA. Urban morphology was characterized using Building Surface Fraction (BSF), Impervious Surface Fraction (ISF), Pervious Surface Fraction (PSF), and Mean Building Height (HM), derived from high-resolution urban datasets (Esposito et al., 2023).

The results reveal significant spatial variability in thermo-hygrometric conditions and thermal comfort across the urban area. Repeated measures ANOVA identified statistically significant differences among monitoring sites, highlighting the presence of marked intra-urban climatic gradients. The most densely urbanized environments exhibited the highest temperatures and the most critical heat stress conditions, whereas greener and less urbanized areas showed lower temperatures and improved thermal comfort. The observed spatial patterns indicate that urban density, surface cover composition, and building geometry play a key role in shaping local microclimatic conditions.

These findings highlight the strong influence of urban morphology on urban climate in Mediterranean cities and provide observational evidence to support the identification of heat-vulnerable areas and the development of climate adaptation and mitigation strategies.