The world is currently in a La Niña pattern, the cool phase of the El Niño-Southern Oscillation (ENSO) cycle that shapes weather across much of the globe. NOAA’s Climate Prediction Center has issued a La Niña Advisory, confirming that both the ocean and atmosphere are behaving consistently with La Niña conditions. This pattern is expected to be weak and short-lived, likely giving way to neutral conditions by early spring 2026.
What La Niña Means Right Now
ENSO is the single biggest natural driver of year-to-year weather variation worldwide. It describes a seesaw in ocean temperatures and atmospheric pressure across the tropical Pacific. During La Niña, sea surface temperatures in the central and eastern Pacific drop below normal, trade winds strengthen, and cooler water wells up along the equator. The key measuring zone, a patch of ocean called Niño 3.4 that sits in the central Pacific, recently recorded a temperature anomaly of about -0.4°C below the long-term average.
That number matters because it tells you this La Niña is mild. Strong La Niña events can push that anomaly to -1.5°C or lower. A weak event still shifts weather patterns, but the effects are less dramatic and harder to distinguish from normal variability.
How Long It Will Last
Forecasters give La Niña a 54% chance of persisting through the December-February 2025-26 winter season. After that, the odds shift decisively toward ENSO-neutral conditions, with a 68% chance of transition by January through March 2026. In practical terms, this La Niña is a one-season event. It arrived in December 2024 after months of neutral conditions and will likely fade before spring.
This matters because it came on the heels of a significant El Niño that ran from June 2023 through May 2024. That warm phase helped push 2024 to the top of global temperature records, 1.29°C above the 20th-century average, making it the warmest year since recordkeeping began in 1850. Global temperatures tend to cool during La Niña years, so 2025 may come in slightly lower, though the long-term warming trend means “cooler” is relative.
What La Niña Does to U.S. Weather
La Niña tilts the odds for seasonal weather in recognizable ways across North America. The jet stream, the river of fast-moving air that steers storms across the continent, typically shifts northward during La Niña winters. That rearrangement produces a few consistent tendencies:
- Northern tier states tend to see colder and wetter conditions, with more frequent storm tracks pushing through the Pacific Northwest, northern Rockies, and Great Lakes region.
- Southern states generally trend warmer and drier, particularly across the Gulf Coast and Southwest. Drought risk increases in parts of Texas, the southern Plains, and Southern California.
- The Southeast faces a somewhat elevated hurricane risk during La Niña years, though that applies to the Atlantic hurricane season (June through November) rather than winter.
Because this La Niña is weak, these shifts may be subtle. A strong cold snap in the Midwest or a dry stretch across the South could be consistent with La Niña, but you won’t necessarily see the full textbook pattern play out in any given week.
The Arctic Oscillation Adds Another Layer
ENSO isn’t the only pattern shaping your weather. The Arctic Oscillation (AO) plays a major role in winter temperatures across the eastern two-thirds of the United States. It describes the strength of the polar vortex, the band of cold air that normally stays bottled up near the Arctic.
When the AO goes negative, that polar vortex weakens and wobbles, allowing blasts of frigid Arctic air to plunge south into the Midwest and East Coast. A positive AO keeps the cold locked up north, steering storms into Alaska and northern Europe while leaving the Lower 48 relatively mild. The AO shifts on a timescale of days to weeks, much faster than ENSO, so its phase can reinforce or counteract La Niña’s influence at any given moment. NOAA’s Climate Prediction Center publishes daily AO readings and 14-day forecasts for anyone tracking short-term cold risk.
Effects on Global Food Production
La Niña’s influence extends well beyond the United States. Australia typically gets above-average rainfall during La Niña, which benefits wheat and grain production but also raises flood risk. Southeast Asia tends to see heavier monsoon seasons. Parts of East Africa and southern South America, by contrast, often face drier conditions that can stress crops.
The broader concern researchers are watching is not any single La Niña but the growing risk of synchronized crop failures, where extreme weather hits multiple major farming regions at the same time. Changes in the jet stream can create persistent heat domes or drought across North America, Europe, and parts of Asia simultaneously. Studies using global crop models estimate that North American yields could drop by around 6% during the most disruptive jet stream configurations, and when those disruptions hit several breadbasket regions at once, the effects on food supply chains multiply. A weak, short La Niña on its own is unlikely to trigger that kind of scenario, but it’s the backdrop against which all other weather variability plays out this season.
Why 2025 Is a Transition Year
The bigger picture is that the climate system is shifting gears. The powerful 2023-2024 El Niño drove record heat globally, and even after it faded, monthly temperature records continued to fall through August 2024. La Niña typically brings a mild cooldown in global averages, but the underlying trend of rising temperatures means even a “cool” year by recent standards would have ranked among the warmest a decade ago.
By mid-2025, the most likely scenario is ENSO-neutral conditions, a neither-El Niño-nor-La Niña state where tropical Pacific temperatures sit near their long-term average. Neutral periods are less predictable because the strong ENSO signal that forecasters rely on fades, leaving smaller-scale patterns like the Arctic Oscillation, the Madden-Julian Oscillation, and regional sea surface temperature anomalies to drive weather. If you’re planning around seasonal weather expectations, the La Niña signal is relevant now but will likely lose its influence within the next couple of months.