A very strong El Niño is set to shape the U.S. winter, with warmer-than-average conditions favored across much of the northern half of the country and wetter-than-average weather favored across the southern tier and along the East Coast, the National Oceanic and Atmospheric Administration (NOAA) said in its Winter Outlook released Oct. 15. The outlook covers December 2026 through February 2027.

Seasonal outlooks are probabilistic. They estimate whether temperature and precipitation are more likely to be above, near or below average, and how drought may change. NOAA notes that the outlook “does not project seasonal snowfall accumulations.”

What the outlook shows

Temperature. Warmer-than-average conditions are favored for northern California, the Pacific Northwest, the Midwest, the Mississippi Valley, much of the East, Alaska, and Puerto Rico and the U.S. Virgin Islands. Near-normal temperatures are most likely in parts of the Southeast, including Florida. Hawaii and much of the Southwest have equal chances of below-, near- or above-average temperatures.

Precipitation. Wetter-than-average conditions are most likely across the southern tier, from the Southwest to the Southeast, and along the East Coast. Drier-than-average conditions are more likely in Hawaii, much of Alaska, the northern Mountain West, some Great Lakes areas and the western Pacific Islands. The Intermountain West, northern Plains, Ohio Valley, and Puerto Rico and the U.S. Virgin Islands have equal chances.

Drought. Through January, NOAA expects drought to improve or end in the Southwest, the Southern Great Plains, the Southeast and parts of the East Coast. Drought is favored to develop or worsen in parts of the northern Rockies, northeastern Oregon and eastern Washington.

The El Niño behind it

NOAA’s Climate Prediction Center (CPC) has an El Niño Advisory in effect. In its Oct. 8 diagnostic discussion, CPC said El Niño “continues to strengthen,” with a strong-to-very strong event likely through January–March 2027 and the chance remaining above 83%. Most Niño indices rose over the past month, with the monthly Niño-3.4 value reaching +2.1°C.

CPC also said chances remain high for a historic event that would exceed the strength of previous El Niño events dating back to 1950, which it defines as +2.5°C or more for a three-month value of the Relative Oceanic Niño Index (RONI). It put that chance at 54% for September–November, 83% for October–December and 70% for November–January.

In the technical discussion issued with the outlook, CPC gave the latest weekly Niño-3.4 value as +2.4°C. Its consolidated forecast and the North American Multi-Model Ensemble (NMME) point to the relative Niño-3.4 index rising to near +3.0°C and +3.5°C respectively, with a general peak in November–January. CPC favors an El Niño of any strength continuing through March–May 2027, and its consolidated forecasts point to potential La Niña conditions in autumn 2027.

How El Niño tilts the odds

“As we know from decades of observations, a very strong El Nino will likely bring a southward and eastward shift to the jet stream for the contiguous U.S.,” said Ken Graham, director of NOAA’s National Weather Service, adding that this “tilts the odds toward stormier weather across the South.”

CPC’s discussion spells out the mechanics. An enhanced Pacific jet stream shifted south and east supports higher odds of above-normal precipitation along the West Coast, extending as far north as the Oregon coast, while the storm track tends to sit south of most of mainland Alaska, favoring drier conditions there. Odds for above-normal precipitation “exceed 70% for some areas in the extreme Southeast and northern Florida.” CPC added that the stratospheric polar vortex is typically stronger and more stable under El Niño and a westerly phase of the quasi-biennial oscillation, which slightly decreases the odds of sudden stratospheric warming events. The forecasters drew on the NMME and Copernicus Climate System (C3S) model ensembles alongside statistical tools.

Why it matters

For drought-hit parts of the South and Southwest, the outlook favors improvement, but NOAA warned of a trade-off. “While higher chances of rain and snow may bring relief to drought-afflicted areas,” Graham said, “too much precipitation on dry soil can fuel destructive flash floods and mudslides.” He urged preparation: “Now is the time for communities and individuals to plan ahead for the upcoming winter.”

NOAA also said it has new winter tools in place. The Weather Prediction Center’s Probabilistic Precipitation Portal, which shows low, expected and high estimates for snow, ice and rain, is now operational, and the National Weather Service will use “Particularly Dangerous Situation” wording in some blizzard and ice storm warnings to flag events of historic severity.

The caveats

A tilt in the odds is not a guarantee. CPC said impacts consistent with El Niño are more likely with an event of this magnitude but are not guaranteed, and it points readers to its seasonal outlooks for specific probabilities. Areas marked “equal chances” are equally likely to come in below, near or above average.

What to watch

NOAA said the next monthly update to the three-month outlook is scheduled for Nov. 19. CPC’s next ENSO diagnostic discussion is due Nov. 12, 2026.

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