September 8, 2026
News | September 7, 2026 | 2 min read
The Pacific Ocean is running hot, and forecasters are no longer hedging. NOAA's Climate Prediction Center now puts the odds of a very strong El Niño this fall and winter above 90 percent, and the World Meteorological Organization said on September 3 that the event could end up stronger than anything in the modern record.
For homeowners, the practical translation is simple: this winter is likely to swing. Wet stretches, warm stretches, sharp cold snaps, and a heating system that runs harder and longer than it did last year.
Here's what forecasters actually know right now, and what to do about it before the first real cold front.
NOAA's Climate Prediction Center issued an El Niño Advisory on August 13, 2026, confirming the event was established. It has strengthened since. July sea surface temperatures in the Niño-3.4 monitoring region ran +1.4°C above average, and CPC now gives greater than a 90 percent chance of a very strong event through fall and winter 2026-27, plus a 69 percent chance the event exceeds +2.5°C during October through December.
That last number matters. Climate scientist Daniel Swain of the University of California puts the likelihood that this becomes the strongest El Niño on record since at least 1950 at roughly 70 percent. WMO Secretary-General Celeste Saulo was blunter: "If this trajectory continues, it may be stronger than anything since our monitoring began, so literally off the charts we have used for the past four decades."
El Niño is a periodic warming of surface waters in the central and eastern tropical Pacific. The official threshold is 0.5°C above average; a "super" El Niño typically peaks near 2°C. That warm water changes where heat and moisture rise into the atmosphere, which in turn shifts the jet stream.
Shift the jet stream, and you shift storm tracks, rainfall, and temperature patterns across North America and well beyond. The cycle typically peaks in intensity during the Northern Hemisphere fall or winter.
El Niño winters follow a reasonably consistent US pattern. The southern tier and Gulf Coast tend to run wetter and cooler as the subtropical jet drives storm after storm across the South.
The northern tier, Great Lakes, and Pacific Northwest tend to run warmer and drier. Neither outcome is a quiet winter for a heating system: the South gets prolonged damp and cold-snap cycling, and the North gets warm spells punctuated by abrupt cold, which is exactly the pattern that has homeowners flipping between heat and no heat for weeks at a time. If your system is going to work overtime, it is worth walking through a winter HVAC maintenance checklist before the swings start.
Because atmospheric heat and water vapor are elevated overall, forecasters also expect a higher likelihood of record temperatures and extreme weather into 2026-27. Northern Illinois University's Victor Gensini noted a strong El Niño "could plausibly push global temperatures to new record levels in late 2026 and into 2027."
Not directly to this fall's fire activity, which is driven by local fuels, wind, and ignition sources. But the bigger picture connects. El Niño years tend to run warmer globally, and that warmth compounds the long-term trends already lengthening fire seasons and intensifying heat waves. Saulo warned the event will "exacerbate drought and heavy rainfall and increase the risk of heatwaves both on land and in the ocean." A warmer, more volatile atmosphere is the backdrop, not the trigger.
Forecasters expect the event to peak toward the end of 2026, most likely between October and December. The WMO puts the odds of El Niño continuing through February 2027 at close to 100 percent, with ocean heat releasing gradually into the atmosphere well after the peak. Expect strong to moderate conditions to persist into spring 2027 before any transition away from El Niño begins.
A strong, unpredictable winter is shaping up. Make sure your HVAC system is ready for it.
A swingy winter means more runtime, more cycling, and more hours with your home sealed up and the same air moving through the same filter. Three things to do before the first hard cold front:
Sources: NOAA Climate Prediction Center, ENSO Diagnostic Discussion (El Niño Advisory issued August 13, 2026); World Meteorological Organization El Niño Update, September 3, 2026; EarthSky, "Will El Niño become supersized? What experts are saying" (Daniel Swain, Victor Gensini commentary); National Weather Service, El Niño and La Niña information; EPA, What is a MERV rating?
