Latest forecast calls for a historic El Niño to peak this winter
Forecasters continued calling for an unprecedented El Niño to continue building over the next couple of months
Exceptionally warm waters in the Pacific Ocean will very likely lead to the strongest El Niño observed since records began in 1950, according to the latest expert analysis.
The U.S. Climate Prediction Center (CPC) expects El Niño to achieve an unprecedented peak during the final three months of this year, which could significantly affect the world’s weather patterns through the autumn and winter seasons ahead.
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A very strong El Niño is imminent
Forecasters with the agency now say there’s a greater than 90 per cent chance that we’ll experience a very strong El Niño through the winter months.
Sea surface temperatures around the equator in the eastern half of the Pacific are running more than 3°C warmer than normal in some areas, which reflects a strong and intensifying El Niño. Water temperatures 50-100 metres beneath the surface are running as much as 10°C above seasonal.
Forecasters use the Relative Oceanic Niño Index (RONI) to judge the strength of an El Niño event. This index measures average sea surface temperature anomalies across a critical swath of the Pacific basin.
The latest forecast calls for the RONI to climb as high as +2.7°C between October and December, and the CPC says there's a 75 per cent chance this will be the strongest El Niño observed since records began in 1950. The current recordholder is a +2.4°C value set during the winter of 1982-1983.
It’s likely that El Niño will continue but weaken heading into the opening months of 2027, potentially sinking toward ENSO-Neutral territory by next spring, during which neither El Niño nor La Niña are present.
How will El Niño affect conditions in the months ahead?
Atlantic hurricane season peaks during the second week of September.
It’s very rare to have no storms in the basin during this time of year, but that’s exactly the case this week largely due to El Niño’s influence.
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Friday, Sept. 11, breaks the record for the Atlantic’s latest first hurricane since the satellite era began in 1966. The previous record is held by Gustav (2002) and Humberto (2013), each of which strengthened into hurricanes at 8:00 a.m. EDT on Sept. 11.
Coastal residents shouldn't let their guards down yet. The Atlantic basin has produced a hurricane every year for at least the last century.
Beyond hurricane season, forecasters expect El Niño to play a central role in Canada’s autumn this year. A milder pattern is likely to dominate much of the country through the coming months.
Strong El Niño events significantly affect winter weather patterns across North America by altering the orientation and strength of the jet streams.
This change can result in mild Pacific air spreading over much of Canada while a cooler, active pattern remains parked across popular vacation destinations in the southern U.S.
But each El Niño has its own characteristics and quirks.
Not every event has the same effects everywhere. Temperature maps during Decembers dominated by El Niño in 1997, 2015, and 2023 all look similar, though with notable differences in where the mildest and coldest pockets of air set up.