Summer Hotspots, Winter Ghosts: How Built Environment Factors Influence Vitality Differentials From Core to Edge in Cold Cities

ABSTRACT Built environment plays a critical role in social sustainability, yet the mechanisms through which it shapes seasonal community vitality under cold climatic conditions remain insufficiently understood. This study conducts a spatiotemporal impact assessment of how built‐environment factors contribute to summer–winter vitality asymmetry—an important dimension of climate‐resilient planning. By integrating multi‐source geospatial data, including mobile positioning data, urban morphology, road network structure, and street‐view image recognition, this research comprehensively identifies the vitality characteristics. Using 1977 neighborhoods in Harbin, an interpretable modeling framework combining MGWR, XGBoost, and SHAP analysis was developed to capture complex spatiotemporal nonlinearities and threshold effects. Results indicate that summer vitality is 1.27–1.46 times higher than winter vitality across all urban zones—meaning the spatial pattern of vitality itself (core vs. edge) does not reverse between seasons. However, the drivers of vitality exhibit a clear reversal: factors such as land‐use mix, property management services, and transport modes show significantly different—and sometimes opposite—effects depending on location (core, peripheral, or fringe) and season (summer vs. winter). Key factors exhibit clear thresholds and spatially heterogeneous impacts, with the top five variables explaining 60% of variation. These findings provide actionable insights for enhancing year‐round social sustainability in cold cities worldwide.