La Niña Has Officially Arrived: Here's What That Means For Fall And Winter In CA

La Niña has officially returned to the Pacific Coast and is expected to stick around for the next five months, the National Weather Service confirmed Thursday.

If the La Niña patterns of the last decade with her swing from historic drought conditions to a rare Southern California blizzard, have taught us anything, it's that this little girl can be unpredictable.

Here's what to know about the climate pattern and how it's expected to affect California.

La Niña, which means "Little Girl" in Spanish, is a climatic pattern event that brings increasing upwelling and cold, nutrient-rich water to the surface of the Pacific Ocean to the west of the United States, according to the National Oceanic and Atmospheric Administration (NOAA).

La Niña is a cold event. The cold waters it brings to the surface of the ocean lead to droughts in the Southern part of the United States and heavy rain and flooding in the Pacific Northwest, according to weather officials.

Below-average temperatures on the surface of the ocean in September indicated the return of La Niña — the fifth time in six years, according to the Washington Post.

The National Oceanic and Atmospheric Administration on Thursday that La Niña conditions emerged in September and are likely to remain though February., according to NOAA.

However, weather officials predict that there is at least a 50% chance that the effects of La Niña will be weak this time around, leading to fewer impacts through the winter.

"Based on recently observed anomalies, the team favors La Niña to continue through winter," the National Weather Service Climate Prediction Center concluded. "In summary, La Niña conditions are present and favored to persist through December 2025 - February 2026, with a transition to ENSO-neutral likely in January-March 2026 (55% chance)".

Although La Niña often means a wetter winter in NorCal, this year’s signal is mixed. NOAA 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.

Even if a La Niña fizzles out this winter, there may be times when weather patterns remains consistent with La Niña — for example, with the warmer weather across the southern U.S., according to AccuWeather, a weather forecasting company.

It also leaves room for ocean factors to influence the forecast, according to AccuWeather Senior Meteorologist and Long-Range Expert Paul Pastelok, including a marine heat wave that will span across much of the Northern Pacific Ocean.

"These waters off the West Coast and extending farther out are very, very important going into our [winter] forecast this year," Pastelok explained.

In Southern California, weather officials expect winter will be hotter and drier than usual, which can exacerbate drought and wildfire conditions.

January could bring rainfall to Southern California, but it is unlikely it will undo the drought conditions brought on by La Niña, according to AccuWeather.

That rainfall will head north by February, and Southern California residents will again be dealing with warm and dry weather, according to AccuWeather.

"If the pattern becomes quite amplified, then near-record highs are possible," Pastelok said. The same is true for most of the Rockies with the exception of Idaho, Montana and Wyoming," according to AccuWeather. "This will set the stage for worsening drought across the West Coast and Rocky Mountains into 2026."

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