The story of the 2026 Atlantic hurricane season begins with El Niño

As ever, each hurricane season has its own story to tell. The story of the 2026 season looks set to be dominated by the development of a strong to very strong El Niño event. El Niño typically increases vertical wind shear across the tropical Atlantic, making it harder for tropical storms to organise and intensify, and generally reducing North Atlantic hurricane risk.

The figure builds on the familiar view of Atlantic hurricane risk as a balance between El Niño / La Niña conditions and Atlantic sea-surface temperatures. Here, that view is adapted in two ways. First, both the Oceanic Niño Index (ONI) and MDR SSTs are shown in relative terms, compared with the tropical mean rather than as absolute values. Positive ONI values indicate more El Niño-like conditions, while negative values indicate more La Niña-like conditions. Second, the colour of each point shows the activity of the hurricane season, while the size of the point shows the scale of insured loss.

The lower-right quadrant captures seasons that are typically lower risk, with cooler Atlantic SSTs and El Niño conditions. The upper-left quadrant shows the opposite: warmer Atlantic SSTs and La Niña conditions, a combination more commonly associated with higher-risk seasons. The current forecasts suggest that 2026 will sit in the upper-right quadrant, with nearly no close precedents it is a more ambiguous part of the risk space. The developing El Niño should act to suppress Atlantic hurricane activity however, the Atlantic and particularly the Gulf SSTs are above the long-term average. If favourable atmospheric conditions occur there is energy available to permit formation and intensification.

In any year a single landfalling hurricane can dominate a season’s loss experience. Past strong El Niño seasons have still produced damaging US hurricane losses. In 1965, Hurricane Betsy became the first billion-dollar hurricane, with losses estimated at around $40bn on a present-day basis. In 1972, Hurricane Agnes, despite only reaching Category 1 intensity, caused widespread flooding, particularly across the north-east US, with present-day losses estimated at around $20bn.

While the strength of the developing El Niño will attract plenty of attention, it should not be mistaken for an absence of hurricane risk.

Our upcoming 2026 El Niño series will explore these questions from several perspectives. Dr Daniel Swain of the California Institute for Water Resources will explain the development and physics of the event. Dr Tom Philp of Maximum Information will consider the implications for decision-making. Dr Francesco Comola of LGT ILS Partners and Ian Bolliger of Reask will examine the application of seasonal signals in ILS markets. Dr Aidan Starr of Inigo will then look beyond hurricane risk, exploring the potential implications for severe convective storm.