The 2026 El Niño rivaled major 1997 and 2015 events
Satellite sea surface height anomaly maps and a NOAA outlook placed the 2026 El Niño alongside the 1997-98 and 2015-16 events.
Background
- NOAA's Oct 8, 2026 outlook assigns an 83% probability to a strong-to-very-strong El Niño through Q1 2027.
- JPL-processed sea surface height anomaly maps from 1997, 2015 and 2026 show the current event rivaling major past El Niños.
- The 2026 El Niño is on track to be bigger than 1997-98 and came on more suddenly, with warm water extending to South America.
- Past rainfall patterns differed: 1997-98 wet California and the southern U.S., while 2015-16 focused rain on Central America and the southeastern U.S.
- A 35-year altimetry record from sea level missions shows sea surface height anomalies signaling El Niño heat buildup.
What happened
On 2026-10-08, NOAA issued an El Niño outlook. A sea surface height anomaly map dated 2026-10-12 was part of the background. The 2026 El Niño was reported as rivaling the 1997-98 and 2015-16 events within a 35-year altimetry record.
What we know
El Niño is a natural climate pattern with global impacts. It involves an atmosphere-ocean feedback loop, and its effects vary according to where warmth appears and how the atmosphere responds.
Normally, trade winds keep warm water piled up in the western Pacific. When those winds weaken, an eastward pulse occurs, and the cycle intensifies in the central and eastern Pacific.
The major reference events are 1997-1998 and 2015-2016. The current El Niño rivals those two milestones.
Josh Willis is project scientist for sea level missions at NASA JPL. Altimetry satellites measure sea surface height, and sea level anomalies signal El Niño heat buildup; the record spans 35 years.
Maps dated 1997-10-13, 2015-10-12 and 2026-10-12 came from TOPEX/Poseidon, Jason-2 and Sentinel-6 Michael Freilich, respectively. JPL scientists processed them. In the color coding, red means higher-than-average sea level, white means normal and blue means lower. Seasonal and long-term trend signals were removed.
The 2026 event is on track to be bigger than 1997 and came on more suddenly than 1997-98. It is similar to 1997-98 in sea level tilt and warm water extent, with warm water extending to South America. Its impacts could be similar to 1997-98.
In 1997-98, there was lots of rain in California and the southern U.S. The 2015-16 event was a heavy hitter with a different character; its warm water did not push against South America as much. Rainfall was concentrated in Central America and the southeastern U.S., and flooding occurred in Mexico.
NOAA issued its El Niño outlook on 2026-10-08. The outlook assigned an 83 percent probability to a strong-to-very-strong event and includes 2027-Q1. The impacts of the 2026-27 El Niño remain to be seen, and El Niño influence propagates through a chaotic atmosphere.
Why it matters
For readers tracking NASA missions, the facts connect JPL sea-level missions, altimetry satellites and a 35-year record to the assessment of major El Niño events. The facts also note global impacts and the role of sea surface height anomalies in showing heat buildup.
What's next
The 2026 El Niño is on track to be bigger than 1997. NOAA’s outlook includes 2027-Q1, and the impacts of the 2026-27 event remain to be seen.
What we are not sure about
- The 2026-27 impacts are not settled; the facts say they remain to be seen.
- NOAA’s outlook gives an 83 percent probability, not a certainty.
- The statement that impacts could be similar to 1997-98 is conditional.
- El Niño influence propagates through a chaotic atmosphere.
Sources
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