Abstract: Urban spatial form is a key factor contributing to the formation of urban distinct microclimate. By analyzing the mobile measurement meteorological data of Wuhan and Zhengzhou in 2016 and 2017, this paper explores the impacts of different climate zones (hot-summer and cold-winter zones, cold areas), different land use categories (commercial and residential), different urban spatial form indexes (sky view rate, greening rate, building height, building density) on the urban thermal environment in summer afternoons. And based on nonlinear regression analysis, it also evaluates the correlations between the urban spatial form indexes and summer afternoon air temperatures. The results showed that the shading effect of buildings is the most crucial factor on summer afternoon temperatures. In Zhengzhou in particular, building density and sky ratio are the most important, with significant correlations. In comparison, the correlation of temperatures and building shading effect in Wuhan is less obvious than in Zhengzhou. It shows that solar radiation plays a decisive role in the rise and fall of temperature in the dry and hot environment, while it is less significant in a hot and humid environment.