La Niña Winter Likely: Here's What It Means For CA

CALIFORNIA — After weeks of record-breaking temperatures, Californians may find themselves wondering about the upcoming winter. Will it be cold and rainy or mild and dry, plunging us further into drought?

The answer may lie with La Niña, the National Oceanic and Atmospheric Administration announced this month. It will also vary depending on where you live in the state. The National Oceanic and Atmospheric Administration has issued a La Niña Watch for the fall and winter of 2025-26, meaning there is at least a 50% chance of a weak La Niña developing later this year.

La Niña is a climate phenomenon that occurs when the central and eastern Pacific Ocean cools down more than usual. It typically causes the northern United States to be cold and wetter than usual, and the southern states to be warmer and drier than usual. That pattern generally extends to California as well. In La Niña conditions, northern California is often colder and wetter, while southern California is warmer and drier, exacerbating drought and wildfire conditions.

El Niño, on the other hand, usually means the reverse. The central and eastern Pacific warms up more than usual, resulting in warmer weather in the north, wetter weather in the south, and often large, unpredictable storms.

Currently, the Pacific remains in ENSO-neutral conditions, meaning neither La Niña nor El Niño are active, but NOAA’s latest predictions expect that to shift around October.

"ENSO-neutral is most likely through the late Northern Hemisphere summer 2025 (56% chance in August-October)," the National Oceanic and Atmospheric Administration announced. "Thereafter, a brief period of La Niña conditions is favored in the fall and early winter 2025-26 before reverting to ENSO-neutral."

According to their August 14 predictions, experts say that there is around a 55% chance La Niña will develop any time from September to November.

California Impacts

Although La Niña often means a wetter winter in NorCal, this year’s signal is mixed. National Oceanic and Atmospheric Administration maps show a 33-40% chance that much of the Bay Area will see seasonal precipitation 33 to 40% lower than normal between December and February. Experts are also currently uncertain whether the Bay Area will see higher or lower temperatures than normal.

The National Oceanic and Atmospheric Administration is more certain that Southern California will be hotter and drier than usual. According to the latest Seasonal Precipitation Outlook for December through February issued Aug. 21, there is a 40-50% chance that much of Southern California, including the entire Southland, will see lower than normal precipitation, and there is a 33-40% chance it will also see temperatures above normal.

Nationwide

Much of the southern U.S., stretching from California’s Central Coast to Florida and up the entire East Coast, is moderately likely to see above-average temperatures this winter. For much of the Midwest, it is equally likely to be above or below normal. Just Washington state and southeast Alaska are likely to see below-average temperatures.

Much of the southern U.S., stretching from the Bay Area in a U-shape to the Washington D.C. area, is moderately likely to see below-average precipitation. Pockets of the Midwest, including Indiana, Ohio, and Kentucky, and much of Montana, Wyoming, and Alaska, are 33-40% likely to see above-average participation. The rest of the country remains uncertain.

On that note, much of this forecast remains relatively uncertain. “Nothing is guaranteed in this business,” said Michelle L’Heureux, scientist at the National Weather Service’s Climate Prediction Center.

NOAA updates its long-range outlooks monthly, and the next forecast is scheduled for Sept. 19. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center website. See here for predictions through November 2026.