US Winter 2026/27 Outlook: El Niño's Impact on America

What El Niño Means for the US Winter

The classic El Niño winter pattern for the United States shifts the Pacific jet stream southward. This creates a predictable chain of effects: wetter in the south, warmer in the north, and stormier in California. The 2026/27 winter is expected to follow this pattern closely.

Temperature Forecast by Region

Pacific Northwest: Warmer than average (70% probability). The southward-shifted jet stream keeps Arctic air away from the region. Portland and Seattle can expect 2-4°F above normal averages.

California: Near normal to slightly above normal. Coastal areas see the strongest warming; inland valleys near baseline.

Midwest & Northeast: Warmer than normal (55-65% probability). The Great Lakes region may see less ice cover than average. The classic El Niño signature here is fewer Arctic blasts.

South & Southeast: Near normal to slightly cooler. The increased cloud cover and precipitation from the active southern jet keeps temperatures down.

Alaska: Significantly warmer than normal (75%+ probability). Alaska sees the strongest El Niño warming signal in winter.

Precipitation Forecast by Region

California: Above-normal rainfall (60-70% probability). Strong El Niño winters historically bring 150-200% of normal precipitation to California. 2026/27 should follow suit, with the atmospheric river season starting earlier than usual.

Southwest: Above normal. Arizona and New Mexico see increased winter precipitation.

Southern Plains & Gulf Coast: Above normal. Texas, Louisiana, and the Gulf states face an elevated flood risk through winter.

Southeast: Above normal. Florida and Georgia see a wetter winter overall.

Pacific Northwest: Below normal. The jet stream is diverted south, so the PNW is actually drier during El Niño winters. This is bad news for the region's snowpack.

Midwest & Northeast: Near normal precipitation, but with a higher fraction falling as rain rather than snow.

Snowpack Implications

California snowpack is likely to be average to above average — good for water supply, but the higher snow line (rain vs snow at higher elevations) could reduce total accumulation at critical watersheds.

The Pacific Northwest snowpack will likely be below average, continuing a multi-year pattern. This has implications for hydroelectric power and summer water supply in the Columbia River basin.

The Northeast may see a below-average snow season overall, with more mixed precipitation events.

Storm Risk

Strong El Niño winters typically produce more storm systems in the southern US. The 2026/27 season is expected to feature:

• Elevated tornado risk in the Gulf states during late winter (January-February)
• More atmospheric river events in California (5-8 ARs categorized as strong or extreme)
• Reduced Nor'easter frequency in the Northeast (the storm track is too far south)

Regional Bottom Lines

California: Wet and stormy. Prepare for flood risk. Good water year expected.

Pacific NW: Mild and dry. Snowpack concerns continue.

South: Wet, cool, stormier. Flood risk elevated.

Northeast/Midwest: Mild, normal precipitation. Less snow than average.

Alaska: Very warm. Impacts on sea ice and winter tourism.