The Pacific Ocean is signalling: El Niño could start as early as this year
One of the signs of a possible El Niño has been spotted in the Pacific Ocean. The Sentinel-6 Michael Freilich satellite, built by NASA and European partners, recorded the movement of warm water across the equatorial part of the ocean to the coast of South America.
This is not a wave in the usual sense, nor is it a tsunami. It is what is called a Kelvin wave, a broad mass of warm water that moves from west to east. The warm water expands, so the ocean level above it rises slightly. That's the kind of change the satellite sees from space.
According to NOAA, there is an 82 per cent chance of an El Niño forming in May-July 2026, and a 96 per cent chance of it persisting through the winter of 2026-2027.
Details
Michael Freilich's Sentinel-6 measures the height of the ocean surface across the planet. This helps scientists see not only the overall rise in sea level, but also temporary changes due to the redistribution of warm water.
In early 2026, the equatorial Pacific Ocean was already experiencing waves of rising sea levels. NASA Earthdata notes that such Kelvin waves typically precede El Niño, although the strength and effects of each episode can vary widely.
When several such warm waves in a row reach the eastern Pacific Ocean, the water off the coasts of Peru, Ecuador and Colombia warms more than usual. This can trigger or intensify El Niño, a climate phenomenon that alters atmospheric circulation and affects precipitation, temperature and storm tracks in different parts of the world.
Why it matters
El Niño can change weather far beyond the Pacific Ocean. In some regions, it increases the risk of heavy rainfall and flooding, while in others it increases the risk of drought and heat waves. It also affects the hurricane season: NOAA is already forecasting a weaker-than-normal 2026 Atlantic hurricane season precisely because of the expected El Niño.
But the impacts can't be painted in advance with a single scenario. Each El Niño differs in strength, development time, and geography of influence.
Background
El Niño is the warm phase of the ENSO climate phenomenon associated with fluctuations in Pacific Ocean surface temperature and atmospheric circulation. Typically, El Niño episodes peak near the end of the year or in the Northern Hemisphere winter.
The name El Niño originated with fishermen off the coast of South America: warm water often intensified on Christmas Eve and worsened fish catches. Now it is one of the most important climate processes, monitored by meteorological services and satellites.
Source
The material is based on the NASA report on observations of Sentinel-6 Michael Freilich and NOAA Climate Prediction Centre data on the probability of El Niño development in 2026.