El Niño is strengthening across the Pacific, and US forecasters say there is a 75% chance that it will reach historic intensity during October-December 2026, exceeding the strength of previous events dating back to 1950.
The National Oceanic and Atmospheric Administration's Climate Prediction Center said there is a greater than 90% chance of a very strong El Niño during the Northern Hemisphere fall and winter 2026-27. The event officially formed in June 2026. On 10 September 2026, NOAA said there was a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27. It was forecast to continue intensifying through the end of the year.
El Niño is present when warming in the equatorial Pacific is accompanied by changes in atmospheric circulation. Current conditions meet both tests, with above-average sea surface temperatures across the east-central and eastern Pacific Ocean and atmospheric patterns consistent with El Niño.
Sea surface temperature anomalies in the eastern equatorial Pacific have exceeded +3.0°C. Ocean temperatures in the eastern Pacific were more than 3 degrees above normal, while anomalies deeper below the surface were more than 10 degrees.
A historic event would require a 3-month Relative Oceanic Nino Index, or RONI, value of +2.5°C or more. The RONI value has already surpassed the 2 degree C threshold. Berkeley Earth projected a peak close to 4°C around November, a level that would make this the strongest El Niño in the observational record.
The World Meteorological Organization said El Niño was expected to continue through the fall and winter, with peak intensity projected for the end of this year. The latest data indicates an 'exceptionally high likelihood of nearly 100%' that the current event will continue until February 2027.
Forecasts suggest El Niño will persist through March-May 2027. There is a possible chance of 55% of ENSO-neutral conditions in April-June 2027. The precise timing of any transition after spring 2027 remains uncertain.
The weather effects of El Niño can vary widely by region. Forecast odds of a wetter-than-normal winter stand at 50 to 60 percent near the California coast. They rise to 70 to 80 percent over southern Georgia and northern Florida. The interior Northwest and the Great Lakes lean slightly drier.
Projections indicate that temperatures could spike by 3C when El Niño fully takes hold in late 2026 or early 2027. Southeast Asia and South America are expected to be particularly badly affected. Southern Africa could face drought, while flooding is possible in the east of the continent.
El Niños can also reduce the number and size of Atlantic hurricanes. The forecast effects are being assessed alongside an ongoing marine heatwave, which has heightened concern about the combined climate effects.
The event could carry a substantial economic cost. A group of economists at Citigroup investment bank estimated that a super El Niño could cause as much as $7 trillion in global economic losses over five years. The estimate does not provide a country-by-country breakdown, and the scale of agricultural losses in major food-producing regions remains unknown.
Forecasters also expect the warming to affect global temperatures. The brief says 2027 is very likely to replace 2024 as the hottest year on record. The precise share of any global temperature increase caused by this El Niño, rather than ongoing climate change, has yet to be established.
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