Howden Re publishes 2025 pre-season hurricane outlook
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The 2025 Atlantic hurricane season, which begins on 1 June and ends on 30 November, is projected to have above-average activity. Colorado State University (CSU) forecasts 17 named storms, nine of which are expected to develop into hurricanes and four to reach major hurricane status (Category 3 or higher).
This anticipated activity represents about 125% of the average observed between 1991 and 2020.
Anna Pergerson (Neely), CCRA CEEM, Managing Director, Head of Catastrophe R&D, Howden Re commented: “Our findings indicate a shift in El Niño–Southern Oscillation (ENSO) dynamics that increasingly support greater storm intensity and longevity. While ENSO phases remain a valuable indicator of seasonal hurricane activity, our data shows that actual losses are more closely influenced by storm tracks, landfall locations, and the level of community preparedness. For example, for the last three years in a row, Florida has experienced a major hurricane starting with Ian in 2022, but impacts to the Florida market varied widely from storm to storm.”
This elevated activity is driven, in part, by unusually warm Atlantic Sea Surface Temperatures (SSTs), which provide necessary fuel for storm development and intensification. Warmer ocean waters offer more energy for storms to grow stronger and sustain themselves.
Additionally, ENSO is currently in a neutral phase and forecasted to stay neutral through the season. Historically, this phase leads to slightly lower but still heightened hurricane activity, similar to La Niña. There is broad agreement among major forecasting groups, including the National Oceanic and Atmospheric Administration (NOAA), Tropical Storm Risk (TSR), and CSU, that these conditions indicate increased activity.
Justin Roth, CPCU, ARe, ARM, CEEM, Associate Director, Catastrophe Analytics R&D Howden Re commented: “This year, a persistently positive Atlantic Multidecadal Oscillation, combined with a neutral-to-La Niña–like El Niño-Southern Oscillation (ENSO) pattern, is expected to reduce vertical wind shear and promote storm development during the peak of the season. Although ENSO is currently neutral and forecasted to remain so, we still anticipate elevated, though somewhat moderated, hurricane activity.”
Notably, the European Centre for Medium-Range Weather Forecasts’ (ECMRWF) seasonal AI-enhanced model, which performed exceptionally well in 2023 and 2024, is also signaling an active season, adding confidence to the consensus outlook.
Several thermodynamic and large-scale drivers are converging to support this above average outlook. Anomalously warm tropical Atlantic Sea Surface Temperatures (SST), which exceed the 1981–2010 mean, are expected to boost heat and moisture fluxes into developing hurricanes. A persistently positive Atlantic Multidecadal Oscillation (AMO) phase, along with a projected neutral to-La Niña–like ENSO phase, should jointly suppress vertical wind shear and foster enhanced cyclogenesis throughout the height of the season.
