Multidimensional urban development reveals contrasting precipitation sensitivities across Chinese cities

Cities are complex functional systems rather than physical assemblages, yet functional heterogeneity in modulating precipitation extremes remains under-explored. We propose a holistic urban fabric framework that redefines urban form by integrating physical form with functional heterogeneity using five metrics: overall construction volume, morphological compactness, vertical filling, porosity, and functional mixing. Using panel data for 225 Chinese cities (2005–2018), we combine trend analysis with causal inference and interpretable modelling to identify predictive causal imprints, nonlinear thresholds, and environmental modulation across three precipitation-extreme indices. Functional mixing shows the strongest CCM imprint strength (ρ) and SHAP-based model attribution among the five metrics, conditioned by climate and built intensity. We distill the evidence into four regional typologies and three planning strategies: surface-flux management, ventilation-oriented morpho-dynamic design, and structural threshold governance. This toolkit provides evidence-based pathways for climate-resilient planning, offering levers to mitigate hydroclimatic risks in rapidly urbanizing and high-density settings across the Global South.