Rooftop photovoltaics (PV) can support rapid urban decarbonization, but their contribution is constrained by the imbalance between PV generation and demand, both shaped by local climate. Growing urban electric-vehicle (EV) deployment creates distributed storage near rooftop PV, shifting PV electricity across time. Here we simulate rooftop PV integrated with EVs as batteries across 5,000 grid cells globally, using hourly meteorology and climate-induced demand. We find that PV-EV systems can supply up to 84% of annual building and mobility electricity demand. Self-sufficiency is highest where daytime demand aligns with generation and seasonal variability remains limited. Using PV capacity factor alone to screen PV-EV potential undervalues 21.9% of the world's 1,000 most populous cities because generation-side metrics overlook the temporal coupling of PV generation, electricity demand and EV storage. Substantial PV-EV potential is concentrated in many low-latitude cities, offering a pathway to cleaner urban energy systems while accelerating progress towards carbon neutrality.
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