<p>Tropical cities endure extreme heat immediately before heavy monsoonal rainfall, creating compounding hazards that strain infrastructure and threaten public health. Although stormwater management typically relies on infiltration and retention, urban cooling requires shading and evapotranspiration, complicating dual-hazard strategies in dense, resource-limited settings. Here, we develop a high-resolution digital climate twin of a neighborhood in Ahmedabad, India, to examine how small-footprint green infrastructure (GI) interventions, traditionally aimed at flood control can also mitigate heat evaluating their thermal co-benefits in terms of air temperature and Physiological Equivalent Temperature (PET). We show that bioretention cells covering only 3% of the area reduce peak daytime air temperature by up to 2 ^∘C and lower physiological equivalent temperature by 4–5 ^∘C, underscoring the importance of assessing thermal comfort rather than air temperature alone. Rather than large-scale urban overhauls, these findings indicate that modest, strategically placed GI can significantly lessen heat risks while retaining flood-mitigation functionality. Our results highlight the value of integrating microclimate perspectives in GI planning, offering a transferable framework for sustainable urban adaptation in rapidly growing, space-constrained regions worldwide.</p>