NASA compares 2026 El Niño with powerful 1997 event using satellite data

NASA Earth Observatory has compared satellite observations from October 2026 with data from October 1997, showing similar patterns of higher-than-normal sea-surface height across the central and eastern equatorial Pacific. The comparison, published on October 23, uses decades of satellite measurements to examine how the current El Niño is developing relative to one of the strongest events in the historical record.

What the satellite images show

The images use sea-surface-height measurements from the TOPEX/Poseidon satellite for October 13, 1997, and the Sentinel-6 Michael Freilich satellite for October 12, 2026. Higher-than-normal sea levels, shown in red, indicate the presence of warmer water that has expanded as it heats.

NASA explains that satellite altimetry provides a way to monitor the buildup of heat in the ocean, including below the surface. The 2026 and 1997 images show warm water extending across the central and eastern Pacific towards South America, although each El Niño develops differently.

Josh Willis, project scientist for sea-level missions at NASA’s Jet Propulsion Laboratory, said the current event came on more suddenly than the 1997–98 El Niño. He noted that the two events now appear similar in their sea-surface patterns, but stressed that the resulting weather conditions cannot be predicted from the visual comparison alone.

What it could mean for India

El Niño can influence the Indian summer monsoon, but its effects depend on other oceanic and atmospheric conditions as well. India’s Ministry of Earth Sciences has said that El Niño is generally associated with weaker-than-normal summer monsoon rainfall, although the strength of that relationship varies. The Indian Ocean Dipole and other climate factors can alter the outcome.

The India Meteorological Department has monitored the developing El Niño alongside other climate indicators and issues forecasts as conditions evolve. The satellite comparison itself does not establish what the event will mean for India’s next monsoon season.

The US National Oceanic and Atmospheric Administration’s October 8 outlook gave an 83% chance of a strong-to-very-strong El Niño continuing through January–March 2027. However, NASA cautioned that the event’s eventual weather impacts remain uncertain because atmospheric responses vary between events.