Seasonal sensitivity of urban moist heat to vegetation and evapotranspiration increases with aridity

Urban greenery and evapotranspiration (ET) are closely linked to urban moist heat, a growing urban climate risk. Vegetation and ET vary with seasonal water and energy dynamics, yet their relationships with urban moist heat remain poorly understood at large scales. Using meteorological and gridded climate data from 86 Chinese cities across four climatic regions, we assessed the seasonal sensitivity of urban moist heat, represented by wet-bulb temperature (TW), to vegetation and ET, and evaluated their predictive importance for TW relative to background climatic factors. Results showed that TW became increasingly sensitive to vegetation and ET as aridity increased, while their predictive importance differed across climatic regions. Vegetation and ET accounted for 39.5% of total feature importance for TW in temperate humid climates, increasing to 73.6% in boreal regions and then decreasing to 22.1% in arid regions. Despite the relatively low predictive importance of vegetation and ET in arid regions, TW showed the highest sensitivity to these factors. This contrast shows that predictive importance and sensitivity do not necessarily follow the same pattern, highlighting the need to consider TW when planning urban greening in arid regions. Recognizing these regional differences can help guide climate-specific urban greening and broader moist-heat adaptation strategies.