The 2025-26 European windstorm season produced 21 named storms, slightly below the historical average of around 22, but seven storms concentrated in Spain and Portugal drove insured losses well above what storm count alone would suggest, according to a Marsh Re report titled "Is the 2025 to 2026 Windstorm Season the New Normal?"
The season's defining characteristic was not frequency but geography and peril mix. A significant proportion of insured losses in the Iberian Peninsula resulted from rainfall and flooding rather than wind, meaning the overall loss picture cannot be read through a standard windstorm lens.
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Sandra Hansen, head of International Peril Advisory at Marsh Re, said: "The 2025-26 European winter storm season was notable for its severity in Southern Europe with intense wind and rain." She added that while storm frequency is expected to remain variable year to year, a warming climate will likely intensify flood risk, with flash flooding in particular warranting closer attention as a dimension of storm-related risk.
Storm Kristin, which struck Spain and Portugal from 28-31 January 2026, generated an estimated €1.727 billion in insured losses, the largest single-storm figure in the report. Storm Ulrike/Nils caused €695 million in French losses from 11-13 February, while Storm Elli/Goretti produced €468 million in losses across France, Belgium and the UK from 8-9 January. Most other tracked storms, including Gabrielle, Detlef/Amy, Helmut/Bram, Leonardo, Marta, Oriana, Yael/Pedro and Rapunzel/Dave, recorded losses below €200 million or had no available data.
Northern European storm activity ran slightly below its historical mean of 19.3, with 18 storms reaching maximum gusts in the region. Southern European storms, defined as those reaching maximum gusts south of 47 degrees north latitude, numbered three, representing 14% of the total, close to the historical mean of 3.2.
A south-shifted jet stream, atmospheric rivers and repeated heavy rainfall combined to produce flooding across Spain, Portugal and parts of France. The North Atlantic Oscillation also influenced conditions during the season, though Marsh Re found it could not alone explain the persistence of southern European storm activity. Historical data in the report show roughly 19% of storms occurring south of 47 degrees north during negative NAO phases, compared with 11% during positive phases. Those shares shifted to 12% and 20% respectively during 2025-26, illustrating a pattern that ran counter to the historical relationship between NAO and southern European storm frequency.
The loss-to-premium ratio in Portugal is the most commercially significant finding in the report for reinsurance brokers and their clients. Marsh Re estimated reinsurer losses from the storm series could reach €1.1 billion to €1.2 billion in Portugal, compared with approximately €250 million in premiums from all non-life contracts. The broker said the gap could put pressure on future renewal negotiations following several profitable years for reinsurers since Storm Lesley in 2018.
Spanish coverage under the Consorcio, the country's public reinsurer, activates only when wind gusts exceed 120 kilometres per hour. Marsh Re's upcoming GCAT Portugal Flood Model, calibrated using data covering roughly 67% market share, is scheduled for release alongside GCAT Iberian Windstorm and Severe Convective Storm models in early 2027, providing more detailed assessments of wind, severe convective storms and flooding across Spain and Portugal.
Catastrophe data provider PERILS puts the season in broader context. Luzi Hitz, product manager at PERILS, said it is relatively safe to conclude the 2025-26 season has ended, with losses described as relatively benign, given that only Goretti and Nils exceeded the organisation's €300 million single-country loss threshold or €500 million Europe-wide threshold.
Hitz noted recent history shows European windstorm seasons can be considerably more severe, pointing to the 2023-24 season's Storm Ciaran, which generated €2.067 billion in insured losses, and the 2021-22 series of Dudley, Eunice and Franklin, which produced a combined €3.851 billion.
Marsh Re's broader conclusion is that the 2025-26 season does not signal a fundamental change in European windstorm activity, but rather illustrates how regional concentration and multi-peril combinations can drive significant losses even in an otherwise average year. The broker expects natural variability to continue driving short to medium-term windstorm activity, while heavier rainfall and flood-related losses could become increasingly important under a warming climate.
For reinsurance brokers with Iberian property or cat exposure in their portfolios, the combination of an adverse loss-to-premium ratio in Portugal and the imminent release of updated flood and windstorm modelling tools makes this a renewal cycle where the data conversation with markets will carry more weight than usual.
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