Outdoor space is essential for urban residents’ daily activities, and thermal comfort is an important indicator to evaluate these places. Currently, there are few studies on city outdoor thermal comfort in western China. This paper, by use of weather stations and questionnaires, studies the relationship between outdoor thermal comfort, adaptive thermal comfort, residents’ social characteristics, and the thermal comfort in Xi’an. In the spring, “neutral” is the most commonly perceived thermal sensation (44.19%), followed by slightly uncomfortable (31.4%). Air temperature is the most important meteorological parameter affecting thermal sensation vote, followed by solar radiation. The thermal acceptable range in Xi’an is 2.69~32.10°C, and the neutral temperature is 17.40°C. In terms of social status, young people (age≤20) have the highest heat sensitivity, while the middle-aged (20< age≤40) have the lowest. And women’s heat sensitivity is higher than that of men. By comparing the thermal comfort ranges of Xi’an, Tianjin, and Harbin, it is found that thermal comfort shows regional and climatic differences. Graphical Abstract

Rapid urbanization has caused environmental problems such as the urban heat island and air pollution, which are unfavorable to residents. Urban traditional blocks are facing the dual challenges of restoration and protection. This paper proposes adaptive transformation strategies for improving the microclimate of traditional areas. We selected Baxian’an Block in Xi’an city, simulated the air temperature and wind speed during summer and winter using ENVI-met, and studied the correlationship between morphological parameters (average building height, building density, enclosure degree, height fall, aspect ratio, and sky view factor) and air temperature and wind speed ratio. The case study revealed that the wind speed ratio of Baxian’an is relatively different in summer, reaching a maximum of 0.61, meaning that the ventilation capacity is significantly affected by the architectural form of the block. Finally, suggestions for the optimal design of the block’s form are provided: the building density should be less than 50%, the average building height should be more than 50 m, the enclosure degree should be less than 0.2, the height fall should be more than 41.7 m, and the sky view factor should be less than 0.5. This study can provide data and support for improving the planning and design standards of traditional residential areas.