After years of La Niña, the Pacific Ocean is flipping. Major global climate models now predict a rapid transition to El Niño later this year, with some forecasts suggesting El Niño could intensify by late summer.
The degree of compression of the shift surprised even seasoned experts, with one forecaster calling it the worst midwinter La Niña in two decades.
This shift was driven in large part by two unusually strong bursts of westerly winds that developed along the equator since January. These outbreaks temporarily weaken the trade winds that sustain La Niña, allowing warm water in the western Pacific to surge eastward.
Government agencies are watching the trend but remain cautious. Not sure yet. A report released Thursday morning by the National Oceanic and Atmospheric Administration predicts a transition to neutral conditions this spring and continuing through the summer. But the agency sees a return of El Niño before the end of the year as increasingly likely.
NOAA’s February outlook shows that La Niña conditions are rapidly receding this spring, with El Niño rates climbing above 50% by late summer and peaking at nearly 60% in the fall. (National Oceanic and Atmospheric Administration)
If a rapid shift in El Niño conditions is confirmed, its effects would extend far beyond the Pacific.
El Niño events typically add to the pressure on rising global temperatures as heat stored in the tropical Pacific is released into the atmosphere. Many of the warmest years on record have coincided with El Niño. Because global ocean temperatures are already rising, even a mild event could cause further warming in 2026 or 2027—although its magnitude will depend on the intensity and structure of the event.
In addition to temperatures, El Niño also restructures rainfall across the tropics. It can weaken the Indian monsoon, change precipitation patterns across South America, and suppress Atlantic hurricane activity by increasing upper-level wind shear.
For California, the relationship is more nuanced than it once seemed. Strong El Niño winters have historically coincided with wet weather in parts of the state, but recent years have shown that pattern is just one driver of West Coast weather. The configuration of the Pacific jet stream, the frequency of atmospheric rivers and short-term climate conditions ultimately determine rainfall amounts.
Nonetheless, strengthening El Niño will shift background conditions toward a more active winter storm track in 2026-27. It does not guarantee heavy rainfall. But this changes the baseline.
Sea surface temperatures in the central equatorial Pacific have begun to rise. Beneath the surface, the signal is stronger. The bursting winds produced downwelling Kelvin waves—pulses of heat that propagated eastward, deepening the heat beneath the water’s surface. In early February, temperatures 100 to 150 meters below the surface in parts of the basin were more than 3 degrees Celsius above average.
Underground thermal reservoirs power the system. If trade winds rebound, surface warming could recede quickly. But as deep-sea heat accumulates and spreads eastward, the likelihood of warming persisting and combining with the atmosphere increases—which ultimately determines El Niño events.
Forecast sea surface temperature anomalies in June 2026 show clear red stripes in the central and eastern equatorial Pacific, which are strong El Niño signals. (ECMWF) (ECMWF)
Recent long-range models show a greater likelihood that Pacific warming will continue and intensify through the summer and that the El Niño threshold will be crossed later this year. Forecast models for spring are less consistent. Nonetheless, the overall trend has shifted decisively towards the development of El Niño later this year.
Official outlooks show more caution, both in terms of the expected arrival of El Niño itself and the timing of such a shift. The National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center continues to maintain a La Niña warning and is favoring a transition to neutral conditions this spring, with neutral conditions most likely remaining throughout the summer. For late summer and beyond, NOAA expects an El Niño event to occur about a 50 to 60 percent chance, an increase compared to the January outlook.
The Japan Meteorological Agency has a slightly forward-looking view, believing that the probability of El Niño occurring in summer is about 60%. Australia’s Bureau of Meteorology remains more cautious, predicting La Niña will become neutral over the coming months, while acknowledging some model guidance suggests El Niño could develop from June.
The most eye-catching thing right now is the accelerated development of the El Niño phenomenon. The Pacific is rapidly reorganizing after a few defining years of La Niña, and the next few months will determine whether that momentum locks into a full-blown El Niño capable of reshaping global weather patterns for the year ahead.
This article was originally published on After years of La Niña, the Pacific is heading toward El Niño. These are California influences.
