This winter, how will the weather be in the United States? Several meteorological agencies have recently given relatively consistent forecasts: the La Niña phenomenon is officially coming. Under this climate pattern, Southern California may become even drier, exacerbating the wildfire situation.
La Niña means “little girl” in Spanish, contrasting with the El Niño (little boy) climate phenomenon. During the La Niña climate phenomenon, the sea surface temperatures in the eastern and central equatorial Pacific Ocean remain cooler, triggering and forming global climate patterns that directly affect weather changes across America.
The Climate Prediction Center (CPC) in the United States announced on Thursday (8th) that the La Niña phenomenon has officially arrived, expected to last from December to February next year, and may transition to El Niño-Southern Oscillation (ENSO) neutral conditions from January to March next year, with a likelihood of about 55%.
According to the latest CPC forecast, the La Niña phenomenon emerged last month, characterized by an expansion of below-normal sea surface temperatures in the eastern and central equatorial regions. Multiple prediction models indicate that La Niña conditions will persist throughout the winter of 2025 into 2026 in the Northern Hemisphere, albeit to a lesser degree.
The Old Farmer’s Almanac predicts that temperatures in most parts of the U.S. will be near normal or slightly above normal; except for a few areas, overall, it will be drier than usual and experience prolonged periods of drought; snowfall in most areas will be below or close to average levels. The Almanac divides the U.S. into 18 weather regions, with Southern California to the San Francisco Bay Area in Northern California listed under Region 16, with only the far northern areas of California falling in Region 15, where Oregon and Washington are located.
The climate characteristics of Region 16 this winter include warm and dry conditions, with below-average precipitation and mountain snowfall; winter storms are expected to decrease, with the most frequent periods in late November, late January, and late February.
AccuWeather’s Chief Long-Range Meteorologist Paul Pastelok believes that the La Niña phenomenon this year is relatively weak, leaving room for other oceanic factors to influence the climate, including an ocean current that spans most of the North Pacific from Japan to the U.S. West Coast.
Chief Meteorologist Merry Matthews of KRDO13 believes that the presence of the La Niña phenomenon will cause the Jet Stream to appear in the northwestern Pacific, the U.S. Midwest Plains, and the Ohio River Valley, leading to above-average precipitation in these regions this season. The precipitation area, based on storm maps, includes some northern areas of California.
Under the La Niña climate pattern, Southern California may experience even drier conditions this winter, further increasing the risk of wildfires.
AccuWeather predicts that the winter climate on the West Coast and in the Rocky Mountains is directly linked to higher ocean temperatures. Due to the warmer-than-average North Pacific temperatures, the likelihood of precipitation is lower, and a warm and dry climate pattern will be prominent in the southwestern U.S., including California, with some areas facing an exacerbation of drought conditions and the risk of unseasonal wildfires.
Although the number of atmospheric rivers this winter will be lower than last year, several storms are expected to arrive in the Pacific Northwest and northern Rockies in December, aiding in snow accumulation in mountainous areas stretching across southwestern Canada and the northwestern U.S.
By January next year, the southward movement of storms may bring the best rainfall opportunities to Southern California and the southwestern U.S., but forecasts indicate that storms are unlikely to alleviate California’s drought; by February, storms will recede northward, and most parts of California and the southwestern U.S. will become warm and dry.