After just a few months, the world's La Niña pattern appears to be on the decline, but its demise will not result in any changes to the winter forecast.
According to NOAA's latest El Niño–Southern Oscillation update, the region known as Niño 3.4 in the central equatorial Pacific remains in a La Niña state - but just barely - as the year comes to a close.
Sea surface temperature anomalies were reported to be around -0.5 degrees Celsius, which is right at the threshold required for the event to be considered a La Niña.
Historical data shows temperatures across the Pacific only reached -0.6 degrees Celsius during the height of the La Niña event, making it a rather weak episode.
Despite the weak nature of the event, weather patterns have resembled a classic La Niña form, with cooler conditions across the northern tier of the country and a dry, warmer Southeast.
Model guidance indicates La Niña is likely to continue through December and into the start of the new year. However, a quick transition to ENSO-neutral conditions is expected sometime before April.
Neutral conditions are defined as water temperature anomalies in the central and eastern Pacific ranging between -0.5 degrees Celsius and 0.5 degrees Celsius.
According to NOAA and some forecast models, the neutral period will be rather brief, with a possible transition into an El Niño during the second half of 2026.
The world was last in an El Niño phase in 2024, and such events regularly occur every two to seven years.
The ENSO status - whether La Niña, El Niño or neutral - plays a significant role in shaping climate patterns across the United States and around the world.
ENSO status impact on 2026
A transition into neutral conditions and possibly even an El Niño phase in 2026 would have significant climate impacts across the U.S. and globally.
Since the start of reliable global temperature records, the planet's warmest years have all occurred during or around El Niño episodes.
A march toward an El Niño in 2026 would undoubtedly bring significant warmth, especially during the second half of the year.
"During El Niño, unusually warm sea surface temperatures in the central and eastern tropical Pacific lead to increased evaporation and cooling of the ocean. At the same time, the increased cloudiness blocks more sunlight from entering the ocean. When water vapor condenses and forms clouds, heat is released into the atmosphere. So, during El Niño, there is less heating of the ocean and more heating of the atmosphere than normal," NOAA experts wrote in a 2022 ENSO blog.
El Niño events are also known to suppress tropical cyclone activity in the Caribbean, Gulf and Atlantic, while the eastern Pacific tends to be more active than normal.
Water temperatures tend to be less robust outside of the Pacific basin, and upper-level winds are often more hostile for tropical development.
When the world could enter an El Niño pattern remains somewhat uncertain, as models tend to struggle with forecasting the progression out of a neutral status.
Errors associated with these predictions are often referred to as the spring predictability barrier, which was last seen in 2024 during the demise of an El Niño - a transition that occurred more slowly than initial projections suggested.
Copyright 2025 Storm Center
