Assessment of Thermal Vulnerability and Analysis of Influencing Factors in Urban Functional Areas of Foshan City, China

To adapt to national climate change strategies, understanding the thermal vulnerability of urban functional zones (UFZs) is critical for enhancing the livability and sustainable development of cities. We address the limitations of existing thermal vulnerability assessments by incorporating human perception into the analysis. Specifically, we introduce the sky openness index to reflect human perception of the thermal environment and examine variations in thermal vulnerability across different UFZs. Using the Extreme Gradient Boosting (XGBoost)-SHapley Additive exPlanations (SHAP) model, we analyze the contributions of 2D and 3D urban form indicators to thermal vulnerability and link these contributions to the unique needs and vulnerability characteristics of UFZs of Foshan City, China in 2023. The results reveal that: 1) high-value heat-fragile areas (1.74–2.00 constitute 10.42% of Foshan City; 2) traffic zone and public-commercial zone exhibit the highest levels of thermal vulnerability; and 3) building height and the normalized building index are the most influential factors, with contributions of |0.06| and |0.03|, respectively. We provide a scientific foundation for developing governance strategies to promote urban resilience.