Widespread extreme precipitation events and associated population exposure have escalated rapidly across China during 1979–2024

Extreme precipitation events with widespread spatial extents (WEPEs) typically lead to greater losses than localized ones, posing severe threats to human health and the economy. Despite their substantial impacts, the spatiotemporal characteristics of WEPEs remain insufficiently understood, hindering effective risk assessment and management. By using observation-based precipitation data over China, we examined the spatial evolution and trends of WEPEs from a three-dimensional (longitude‒latitude‒time) perspective from 1979 to 2024. WEPEs were defined as extreme precipitation events whose projected areas ranked in the top 1% of all events. WEPEs were predominantly concentrated in southern and eastern China, where they exhibited greater spatial extent and intensities than they did in other regions. During 1979‒2024, the WEPE frequency increased significantly ( p < 0.05) by 0.52 events per year, accompanied by significant increases in accumulated area (0.61% per year, p < 0.05) and mean area (0.48% per year, p < 0.05), while projected area showed a relatively weak upward trend (0.21% per year, p > 0.05). Most WEPE metrics showed non-monotonic relationships with temperature and peaked at 22–23 °C, whereas the mean and max intensity increased monotonically with rising temperature. Exposed population and exposed duration to WEPEs in China increased markedly (1.17% and 1.53% per year, both p < 0.05), driven by both WEPE variations and demographic factors. Our findings could offer useful references for climate adaptation and flood risk management under a warming climate.