Abstract: Taking the 12 prefecture-level cities of Inner Mongolia Autonomous Region as the study area, this study constructs a climate carrying capacity evaluation framework based on the Pressure–State–Response (PSR) model, incorporating climate natural capacity, extreme climate event pressure, urban climate pressure, and urban coordinated development capacity. Using multi-source data from 2003 to 2023, the spatiotemporal evolution of urban climate carrying capacity is systematically analyzed. Key driving factors are further identified through Spearman correlation analysis and multicollinearity diagnostics, and multiple machine-learning models are compared, with SHAP applied to interpret the direction, magnitude, and regional heterogeneity of driving effects. The results indicate that: (1) climate carrying capacity exhibits pronounced stage-wise fluctuations over the study period, jointly driven by state improvement, pressure alleviation, and response restoration; spatially, higher levels are observed in central and western Inner Mongolia and lower levels in the eastern region, with regional disparities gradually narrowing while the overall pattern remains stable; (2) the random forest model demonstrates the best predictive performance, identifying sunshine duration, the proportion of science and technology expenditure, population density, the share of the tertiary industry, environmental protection investment, and per capita daily comprehensive domestic water use as key drivers; and (3) driving mechanisms display significant regional heterogeneity, with resource-based and ecologically fragile areas being more sensitive to technological and governance inputs, highly urbanized and industrialized areas being more constrained by resource pressure, and ecologically constrained regions being more prone to weakened climate regulation capacity under the combined effects of industrial expansion and climatic factors. These findings provide scientific support for differentiated climate adaptation and carrying capacity regulation strategies in arid and semi-arid regions.