Effects of physical factors on winter thermal comfort in urban street canyon

Outdoor thermal comfort in urban street canyons is shaped by interacting factors (meteorological, spatial, and psychological factors). Among the physical environmental parameters, surface albedo (ALB), Green View Index (GVI), and Sky View Factor (SVF) may all influence pedestrians’ winter thermal perception, yet their combined roles remain insufficiently understood. This study investigated winter thermal perception in urban street canyons through field measurements and subjective questionnaires conducted at sites with different physical environmental characteristics. The results showed that the overall neutral temperature, expressed as Physiologically Equivalent Temperature (PET), was 16.61°C. Sites with higher ALB tended to show higher neutral temperatures, whereas site-level variations associated with GVI and SVF were less regular. Regression analyses further indicated that Physical Environmental Satisfaction Vote (PESV) was associated with ALB, GVI and SVF under specific time periods and PET intervals. Because PESV was coded from 0 (satisfied) to 4 (intolerable), positive coefficients indicate reduced satisfaction, whereas negative coefficients indicate improved satisfaction. For example, higher ALB under PET = 1°C–5°C was associated with improved satisfaction, while the associations involving GVI and SVF varied across time periods and thermal conditions. Overall, winter thermal perception in street canyons appears to be shaped by the combined and context-dependent influence of surface reflectivity, visible greenery, and sky openness. These findings should be interpreted as empirical associations rather than as definitive causal effects.