El Niño's calm Atlantic, busy Pacific — and the year after.
El Niño strengthens the upper-level westerly winds over the Caribbean and tropical Atlantic, and that wind shear tears developing hurricanes apart. Over the Pacific it does the opposite: warmer water and weaker shear feed longer-lived, stronger storms. This route checks the textbook against every season since 1950, counts how often it held, and asks the question for 2027: what happens in the Atlantic the year after a strong El Niño?
Every season, sorted by ENSO phase
El Niño is only half the Atlantic story
Atlantic energy against Atlantic warmth
Each dot is a season: its ACE against how much warmer the hurricane nursery (the Main Development Region) was than the tropics as a whole, August–October.
The year after a strong El Niño: the 2027 question
Atlantic ACE in the El Niño season and the season after
Grey tick: the normal for that year (the trend line through the neutral seasons). The second dot is coloured by the ENSO phase the following season turned into.
Hurricanes that reached the U.S. coast
U.S. hurricane landfalls by the ENSO phase of the season
Storms that crossed the coast of the lower 48 as a hurricane (one count per storm per season), 1950–2025. Small print: the 95% interval.
Every U.S. landfalling hurricane since 1950, by phase
2026 to date, against every El Niño season
How this is counted
Accumulated cyclone energy (ACE) adds up a season's wind: the square of each storm's maximum sustained wind (knots), every six hours (00, 06, 12 and 18 UTC only), while it is a tropical or subtropical storm of at least 34 kt, divided by 10,000. It rewards strong, long-lived storms and barely counts short-lived ones, which makes it the best single measure of a season and the least sensitive to storms that satellites now catch but older records missed. Named storms reached tropical- or subtropical-storm strength; hurricanes (typhoons in the West Pacific) reached 64 kt; major hurricanes reached 96 kt, category 3.
ENSO phase of a season is the Oceanic Niño Index for August–October, the heart of the hurricane season: El Niño at +0.5 °C or more, La Niña at −0.5 °C or less. The seasons are labelled by their calendar year. Normal is the straight-line trend through the neutral seasons only, so a slow change in the record (or in how storms were measured) is not mistaken for ENSO. Medians carry 95% bootstrap intervals (whole seasons resampled); shares carry 95% Wilson intervals; the El Niño–La Niña comparison is a permutation test.
Periods: the Atlantic from 1950 (the first year of the ONI); the East and Central Pacific from 1971, when satellite coverage made its record complete; the West Pacific (JTWC, one-minute winds) from 1965. U.S. landfalls are HURDAT2 landfall records on the coast of the lower 48. Atlantic warmth is ERA5 sea-surface temperature over 10–20°N, 85–20°W minus the 30°S–30°N tropical mean, August–October, as a departure from 1991–2020; "relative" warmth is what matters for hurricanes (Vecchi and Soden 2007) and carries almost no global-warming trend. 2026 comes from the provisional IBTrACS tracks (NHC, CPHC and JTWC advisories), which the post-season review will revise.