Investigating the Role of Climate Change in the 3 May 2025 Western Europe Hailstorm Using Atmospheric Analogues

On 3 May 2025, a severe hailstorm affected Paris and parts of western Europe. We assess whether anthropogenic climate change contributed to its intensity using ERA5 reanalyses and an analogue-based attribution framework. The synoptic pattern featured a cut-off low and a surface cold front following several warmer-than-normal days. We identify circulation analogues to 3 May 2025 in two periods, namely a cooler “past” (1974–1999) and a warmer “present” (1999–2024). We then compare thermodynamic conditions under otherwise similar large-scale flow. Hail probability and size are estimated with two models: (i) a logistic formulation using Convective Available Potential Energy (CAPE), deep-layer wind shear, and convective precipitation, and (ii) an extended model including freezing-level height and 850 hPa temperature, tailored to European hail environments. Models are calibrated with ˆIle-de-France observations and validated independently. Present-day analogues exhibit significantly higher CAPE, a higher freezing level, and similar deep-layer shear, yielding larger hail probability and size. These results indicate that human-induced warming likely enhanced the hailstorm severity in this synoptic setting.