Very strong El Niño puts U.S. winter snowfall odds in focus
NOAA's Climate Prediction Center says El Niño is strengthening, with a greater than 90% chance of a very strong event through winter 2026-27. Historical patterns tilt more southern snow risk and less northern snow — if cold air cooperates.
El Niño is strengthening across the equatorial Pacific. NOAA's Climate Prediction Center says there is a greater than 90% chance it becomes a very strong event through Northern Hemisphere fall and winter 2026-27. CPC's Sept. 21 status update keeps an El Niño Advisory in place. Equatorial sea-surface temperatures are above average across the east-central and eastern Pacific, and the atmospheric circulation matches El Niño. For October–December 2026, CPC also cites a 75% chance of a historic event whose three-month relative oceanic Niño index would exceed prior El Niños dating to 1950.
That outlook is why early winter snowfall talk is back. A Sept. 22 Weather.com wrap notes that El Niño impacts usually spread across the United States from December through March. In a stronger event, the southern branch of the jet stream tends to wet the southern tier from parts of California and the Desert Southwest into Florida and the Southeast — with more snow only where the air is cold enough. Much of the northern U.S. typically runs milder and drier in strong El Niño winters, from the Northwest and northern Rockies into the Northern Plains and Midwest.
NOAA Climate.gov's historical snowfall composites back that north–south split. During El Niño winters, the jet stream often shifts south and extends east. Composites show a stripe of above-average January–March snowfall across parts of the southern half of the country — strongest in higher, colder western elevations — and below-average snowfall around the Great Lakes, interior New England, the northern Rockies, the Pacific Northwest, and much of Alaska. Stronger El Niño events tend to amplify those average patterns. Climate.gov stresses the maps are averages, not forecasts: a few heavy snow winters can skew the mean, and year-to-year swings stay large.
Climate change adds another caveat. After removing long-term trends from the El Niño composites, Climate.gov still notes that contiguous U.S. winter snowfall has trended downward from 1959 to 2023, while colder northern latitudes such as Alaska have seen some winter increases. CPC seasonal temperature and precipitation outlooks already fold in ENSO plus long-term trends and soil moisture; they shift regional odds without guaranteeing local snow totals.
For travelers, ski towns, and city planners, the confirmed public beat is the El Niño Advisory and the very-strong outlook into winter 2026-27. The next CPC ENSO Diagnostics Discussion is scheduled for Oct. 8. Until then, official CPC outlooks — not viral snow maps — remain the scientific baseline for how snowfall odds shift by region.
Where outlets agree NOAA CPC and NOAA Climate.gov agree El Niño is present and strengthening, and that El Niño winters historically tilt U.S. snowfall odds toward more snow across parts of the southern tier and less snow across much of the northern United States and Alaska.
Where they differ Emphasis still differs. Weather.com stresses a historic-super framing and southern snow only if cold air arrives; Climate.gov stresses that snowfall composites are averages — not forecasts — and that long-term warming has cut contiguous U.S. winter snowfall; CPC centers on ENSO strength probabilities and seasonal outlooks rather than city-level snow totals.