NOAA: Weak La Niña forms, may last into 2026, shaping winter weather

The National Oceanic and Atmospheric Administration said Thursday that La Niña conditions have formed in the equatorial Pacific, marking the return of the cool phase of the El Niño Southern Oscillation and raising the prospect of altered weather patterns worldwide through the Northern Hemisphere winter. Forecasters said the event is most likely to be weak and could last into early 2026, with particular concern for drought risks in parts of the Americas and shifting winter weather across the United States.

La Niña develops when sea surface temperatures across parts of the central and eastern equatorial Pacific fall below normal and the atmosphere responds with characteristic wind and rainfall changes. NOAA and the U.S. Climate Prediction Center reported expanding below-average ocean temperatures and easterly low-level winds consistent with a La Niña pattern. Michelle L'Heureux, lead scientist on NOAA's ENSO team, said there is "a three out of four chance it will remain a weak event." The Climate Prediction Center said the pattern is likely to persist into February 2026 but noted a roughly 55 percent chance of a return to neutral conditions by early 2026.