Scientists with the United States National Aeronautics Space Administration (NASA) said a powerful climate signal is building across the tropical Pacific, and satellites can see it rising in the ocean. El Niño returned in June 2026, marked by warmerthan-average waters in the central and eastern equatorial Pacific.
The National Oceanic and Atmospheric Administration (NOAA) declared the event on June 11 after sea surface temperatures stayed at least 0.5 degrees Celsius (0.9 degrees Fahrenheit) above normal for several months.
By then, NASA and its partners were already tracking another warning sign from space: higher sea surface height. That rising ocean surface matters because warm water expands. When a large mass of warm water spreads across the Pacific, satellites such as Sentinel-6 Michael Freilich can detect the subtle lift in sea level. In this case, the height changes are not just a surface detail.
They reveal where the ocean is storing heat below the surface, which can help show whether El Niño has enough energy to reshape weather patterns months later. El Niño can shift rainfall, heat, and storm tracks around the world.
It often raises the odds of wetter conditions across the U.S. Southwest while increasing drought risk in parts of the western Pacific, including Indonesia and Australia. Its strongest effects often arrive during Northern Hemisphere winter, when changes in the tropical Pacific can ripple through the atmosphere and alter weather far from the ocean where they began.
The June 8, 2026, satellite map showed higher-thanaverage sea levels across parts of the central and eastern Pacific. Red areas marked elevated sea surface height, white showed near-normal levels, and blue indicated lower-than-average water levels.
Scientists removed seasonal patterns and longterm sea level trends from the data so shorter-term signals, including El Niño, stood out more clearly.
The observations came from the Sentinel-6 Michael Freilich satellite, launched in 2020 by NASA and led by ESA (European Space Agency). Scientists at NASA’s Jet Propulsion Laboratory (JPL) processed the data. The buildup did not appear suddenly. Earlier in spring 2026, Sentinel-6 detected large pulses of warm water, called Kelvin waves, moving eastward across the equatorial Pacific.
