Synergistic effects of spatial morphology and thermal comfort on pedestrian activities in residential areas: A field-based study in Wuhan, China

Both outdoor attendance and behavioral activities are significantly affected by the interplay between spatial morphology and environmental comfort. However, limited research has clearly elucidated the interrelationship among outdoor spatial morphology, thermal comfort, and spatial vitality. The aim of the study was to explore the synergistic influence mechanism of outdoor spatial morphology and thermal comfort on pedestrian activities to predict the usage patterns of different communal spaces. A comprehensive dataset covering microclimate, thermal sensation, and outdoor activities was obtained through field measurements over six typical days in both summer and winter. By introducing structural equation modeling (SEM), this study identified the influence paths by which spatial, environmental, and behavioral factors affect spatial vitality. The results indicate that: (1) The effective outdoor thermal comfort temperature range for Wuhan residents is between 7.77 °C and 36.87 °C, with peak comfort occurring at a Universal Thermal Climate Index (UTCI) of approximately 22.33 °C. (2) In winter, outdoor activities peak around 11:00 a.m. and 4:00 pm.; in summer, peaks occur before 10:00 a.m. and after 4:00 pm. Spatial connectivity, accessibility, and sky view factor were key spatial factors influencing vitality (factor loadings: 0.84, 0.71, and 0.80). Thermal comfort was the most influential thermal perception variable (loading = 0.65), while age was the most significant individual factor (loading = 0.85). (3) Greater spatial openness enhances residents’ environmental sensitivity, with steeper and more accurate UTCI–activity relationships. This study quantifies how spatial morphology, outdoor environment, and demographics shape spatial vitality, offering guidance for optimizing residential outdoor space design.