Climatology and Trends in Spatial Scales of Extreme Precipitation Over Land in the Contiguous US

Abstract Extreme precipitation (EP) poses a severe risk under a changing climate. Here we use daily gridded precipitation data (1980–2024) and a connected‐component labeling algorithm to characterize the climatology and regional trends of daily EP spatial scale over land in the contiguous United States (US). EP event sizes follow a logarithmic distribution; thus, the largest‐area EP events disproportionately drive total yearly EP area. These largest‐area events exhibit different seasonality and have higher average intensities than smaller events. We find a widespread decline in small‐area EP events and overall days with EP, concentrating EP into fewer days per year but with larger areas on those days. In the eastern US, we find a rising frequency of large‐area events, driving significant growth in yearly EP area. These findings highlight the importance of spatially informed analyses in understanding the changing nature of EP for better climate risk assessments, adaptation planning, and economic loss projections.