A strong El Niño is under way
The central equatorial Pacific (Niño 3.4 region) is +3.3 °C warmer than normal (week of 14 Oct 2026), and off northern Peru (Niño 1+2) +5.2 °C. NOAA's official index (RONI) reached +1.69 °C in JAS 2026. NOAA status: El Niño Advisory. ENFEN status: Alerta de El Niño Costero.
Niño 3.4: 2026 versus major events
Weekly anomaly (°C) from January to December of each onset year.
Chance of El Niño
Official outlook by season · Issued Oct 2026
NOAA synopsis: “El Niño continues to strengthen, with a strong-to-very strong El Niño likely through January-March 2027 (remaining greater than an 83% chance).”
Official RONI outlook
Likely range of the index over the coming seasons, next to observations.
What is El Niño?
It is the unusual warming of the central and eastern equatorial Pacific, coupled with weaker trade winds. It recurs every 2 to 7 years, lasts 9 to 18 months, and reorganises tropical rainfall, disrupting weather across much of the planet.
Coastal El Niño
Off Peru and Ecuador the sea can warm even when the central Pacific does not (as in 2017). That is why Peru uses its own index (ICEN, Niño 1+2 region) and its own alert system, run by ENFEN.
See Peru →Effects around the world
Drought in Indonesia, Australia and southern Africa; heavy rain in East Africa and southern South America; a weaker Indian monsoon; fewer Atlantic hurricanes; and globally warmer years.
See global impacts →