La Niña is officially here, and it looks like it could have a significant impact on the 2025-26 winter season with cooler, potentially snowier conditions for parts of the U.S. On October 9th, 2025, NOAA’s Climate Prediction Center announced that La Niña conditions emerged in September 2025 and are favored to persist through December 2025-February 2026, with a 55% chance of transitioning to ENSO-neutral by January-March 2026.
La Niña Is Here
La Niña conditions took hold in September 2025, driven by below-average sea surface temperatures (SSTs) spreading across the central and eastern equatorial Pacific. The Niño-3.4 index, a key indicator, hit -0.5°C, with other Pacific regions ranging from -0.1°C to -0.4°C, while chilly subsurface waters reached 200 meters deep in the east. Easterly low-level winds, westerly upper-level winds, enhanced convection over Indonesia, and suppressed activity near the Date Line, paired with a positive equatorial Southern Oscillation index, confirm La Niña’s presence.
This event is expected to be weak, with the Niño-3.4 index staying between -0.5°C and -0.9°C through the Northern Hemisphere winter. The International Research Institute (IRI) and North American Multi-Model Ensemble forecasts align, predicting La Niña’s hold through December 2025-February 2026. While not a powerhouse, this weak La Niña could still influence weather patterns, nudging seasonal forecasts like those from NOAA’s Climate Prediction Center toward cooler and wetter conditions in key areas.
La Niña conditions are present and favored to persist through December 2025-February 2026, with a transition to #ENSO-neutral most likely in January-March 2026 (55% chance). A #LaNina Advisory is now in effect. https://t.co/5zlzaZ0D9Z pic.twitter.com/BdppfqhjMU
— NWS Climate Prediction Center (@NWSCPC) October 9, 2025
What Does This Mean for Winter?
The El Niño-Southern Oscillation (ENSO) cycle is a recurring climate pattern that swings sea surface temperatures in the tropical Pacific by 1-3°C every three to seven years, impacting global weather. La Niña, its cooler phase, strengthens trade winds, boosts rainfall in places like Indonesia, and dries out the central Pacific. These shifts ripple outward, often amplifying the jet stream’s waves and altering temperature and precipitation across North America, especially during winter.
For the U.S., La Niña typically brings colder, wetter conditions to the northern tier, from the Pacific Northwest to the Upper Midwest, while the South leans drier and warmer. Ski resorts in the northern Rockies, Cascades, and northern Sierra could see 10-20% above-average snowfall. However, this weak La Niña may temper the extremes, meaning fewer mega-dumps but still reliable snow for northern resorts, with southern areas like New Mexico or the southern Appalachians potentially seeing spottier conditions.
If you’re planning a winter getaway, northern resorts are your best bet for consistent snow, though local weather quirks can always shake things up. Keep an eye on NOAA’s seasonal outlooks for the latest resort-specific forecasts as we head into November.
