Seasonal Effects of Urban Morphology on Street-Level Land Surface Temperature in Hong Kong

Global climate change has intensified extreme heat events, particularly exacerbating Urban Heat Island (UHI) effects in high-density cities, where challenges to public health, energy demand, and sustainable urban development are amplified. Hong Kong, a hyper-dense subtropical city constrained by scarce green spaces, vertical building clusters, and narrow streets, exemplifies severe thermal stress. While existing studies focus on remote sensing-based thermal analyses, this research addresses critical gaps by investigating street-level land surface temperature (LST) dynamics across seasons and integrating multisource geospatial data (remote sensing, street views, and architectural datasets). Six urban morphology metrics—Green View Factor (GVF), Building View Factor (BVF), Sky View Factor (SVF), Building Coverage Ratio (BCR), Building Volume Density (BVD), and Frontal Area Density (FAD)—were analyzed using an XGBoost-SHAP framework to quantify seasonal impacts and variable interactions. Key findings include: (1) Significant LST seasonality, with summer temperatures reaching 28.65–39.69°C and winter lows of 14.45–28.23°C, alongside persistent heat hotspots in urban cores (Kowloon/Northern Hong Kong Island) and cooler zones in vegetated/waterfront areas; (2) GVF consistently mitigates heat (peak cooling: -3.1°C in summer), whereas SVF aggravates warming (+2.8°C in winter); (3) Building morphology metrics (BVF/BCR/BVD/FAD) drive summer heating but exhibit limited influence in cooler seasons. SHAP analysis reveals synergistic interactions, such as winter BCR-GVF amplification and year-round GVF-BVF-SVF interplay. The study proposes targeted urban morphology optimization—expanding green infrastructure, redistributing building density, and enhancing street ventilation—to reduce UHI intensity by 15–22% in Hong Kong. These strategies provide a transferable blueprint for improving climate resilience and sustainable development in high-density subtropical cities globally.