A weather-changing La Niña has emerged in the Pacific Ocean, increasing the risk of drought in California and crop-growing regions in Brazil and Argentina while also bringing cold to the US Midwest and a milder winter to New York and the US East Coast.
The cyclical La Niña, which occurs when the Pacific’s surface cools and the atmosphere above it reacts, formed last month and will likely last through February 2026, the US Climate Prediction Center said in its latest outlook Thursday. The phenomenon is not projected to be strong, so typical impacts could be limited.
“Because we expect this event is most likely to be weak, we would also expect that the changes in the tropical Pacific Ocean may not as effectively push the global circulation around,” Michelle, L’Heureux, a forecaster with the Climate Prediction Center, said in an email.
La Niña is closely watched because it significantly shifts weather in ways that can affect agriculture and energy markets globally. The phenomenon increases chances of dry conditions in Southern California and parts of South America, potentially spreading drought across southern Brazil and Argentina affecting crop yields. It can also signal cooler weather in Japan, northwest Canada and the US Great Plains and Upper Midwest. The colder temperatures can affect heating demand and, in turn, natural gas markets.
During some La Niña winters in the US, the storm track drifts across the Northeast bringing more snow and rain to inland areas. For cities such as New York and Washington, this can mean rainier winter storms that usually lead to less snow through the season. The current forecast calls for a milder winter along the East Coast, but that follows long-term trends.
In recent years, La Niña has appeared almost twice as often as its warmer counterpart El Niño, L’Heaureux said. Since about 1980, there have been more La Niña-like conditions across the tropical Pacific, she said. El Niño Southern Oscillation, or ENSO, is the scientific name for the cycle.
“It’s hard to say how much the longer-term trend is being mixed up with seasonal ENSO variations that we experience and notice, but I know this is an active area of research,” L’Heureux said.
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