In December 2025 and January 2026, meteorologists observed a rare phenomenon in the Western Pacific: two episodes of “Westerly Wind Bursts” of record intensity. These gusts of tropical wind, which blow near New Caledonia and Papua New Guinea, have reversed the usual trade winds and are now pushing the warmest waters on the planet eastward, towards South America.
These winds trigger the formation of Kelvin waves, gigantic slow-moving ocean waves that carry heat beneath the surface of the Pacific. By February and March 2026, this warm water will reach the eastern Pacific, marking the end of La Niña and the start of a new El Niño cycle.
El Niño is coming, see you between May and August 2026
The European Center for Medium-Range Weather Forecasts leaves no room for doubt, El Niño will develop from summer 2026. Climate models all converge towards the same timetable with a transition to neutral conditions in February-March 2026, followed by a development of El Niño between May and August 2026. The probability exceeds 60% for autumn 2026, with a peak expected during winter 2026-2027.
This speed of transition worries climatologists. The current La Niña phase, although established since November 2025, is already showing signs of weakness and should completely disappear before March.
2027, the year of all records
If 2026 already promises to be very hot with around 1.4°C above pre-industrial levels, it is especially 2027 that makes scientists tremble. Kevin Trenberth, distinguished researcher at the National Center of Atmospheric Research, recalls a crucial phenomenon, global temperatures peak about three months after the peak of El Niño.
With an El Niño reaching its maximum during the winter of 2026-2027, extreme heat will therefore be felt in the spring and especially during the summer of 2027. Climatologist Zeke Hausfather anticipates that this year will be “considerably warmer” than 2026, with the potential to set a new absolute record, even surpassing the 2024 peak.
A climatic staircase from which we never come down
US Department of Defense meteorologist Eric Webb uses a metaphor where he compares climate change to an ascending staircase. Due to the continued increase in greenhouse gases, the climate system fails to dissipate the heat released by one El Niño before the next one occurs and pushes the base temperature even higher.
This mechanism explains why each new El Niño cycle systematically beats the records of the previous one. The 2023-2024 period had already shown the devastating power of this combination of El Niño and anthropogenic global warming, making 2024 the hottest year on record. But this record is likely to be short-lived.
Unprecedented ocean heat
The current context is all the more alarming given that 2025 was the ninth consecutive year in which records for global ocean heat content were broken. The Western Pacific Warm Pool, this area of the Pacific which is home to the warmest waters on the planet, also set temperature records in 2025.
This accumulation of heat in the oceans acts as a time bomb. During El Niño, this energy is released into the atmosphere, causing global temperatures to rise sharply. The oceans, which until now played a moderating role by absorbing excess heat, are temporarily becoming amplifiers of warming.
Concrete impacts from 2026
The consequences of this climatic shift will be felt well before the summer of 2027. From 2026, El Niño will influence the hurricane season, the phenomenon generally tending to reduce activity in the Atlantic by increasing wind shear, although exceptionally high ocean temperatures could counterbalance this effect. In terms of global precipitation, Australia and Indonesia at risk of prolonged droughts and extreme heatwhile some regions of the eastern Pacific will see increased precipitation. In Europe, winters marked by El Niño are generally more disturbed, humid and stormy in France, with a mild and humid start to winter followed by a colder and drier end.
Towards summers at 50°C in Europe?
If the summers of 2026, 2027 and 2028 are set to be the hottest in historythey will unfortunately not be the last to wear this title. As long as greenhouse gas emissions continue at their current rate, each new El Niño cycle will set new records.
The 2026-2028 period could also mark a symbolic milestone: that of the threshold of 1.5°C of global warming compared to the pre-industrial era over an average of three years. This threshold, set by the Paris Agreement as a limit not to be exceeded, still seemed distant a few years ago. It could be reached by the end of this decade.
A scientific certainty, not an inevitability
The forecasts are formal, climate models show rare convergence and high confidence in the development of El Niño for 2026. Oceanic and atmospheric indicators all point in the same direction. The climate machine is in motion, and nothing can stop it in the short term.
But while future record summers are inevitable, the magnitude of future records still depends on actions taken today. Every tenth of a degree counts and the difference between a world at +2°C and a world at +3°C is measured in human lives, ecosystems preserved and disasters avoided.
The years 2026 to 2028 will not only be the hottest in history, they will also be a life-size test of our collective capacity to cope with a climate that is definitively shifting into a new era.
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