NOAA's National Centers for Environmental Information
Introduction
El Niño and the Southern Oscillation, also known as ENSO is a periodic fluctuation (i.e., every 2–7 years) in sea surface temperature (El Niño) and the air pressure of the overlying atmosphere (Southern Oscillation) across the equatorial Pacific Ocean. The presence of an El Niño, or its opposite – La Niña – sufficiently modifies the general flow of the atmosphere to affect normal weather conditions in many parts of the world. Learn More…
CPC Synopsis Updated: 14 August 2025
ENSO-neutral is most likely through the late Northern Hemisphere summer 2025 (56% chance in August-October). Thereafter, a brief period of La Niña conditions is favored in the fall and early winter 2025-26 before reverting to ENSO-neutral. More information…
ENSO Indicators
Southern Oscillation Index (SOI)
Information on the Southern Oscillation Index (SOI), a standardized index based on the observed sea level
pressure differences between Tahiti and Darwin, Australia
Sea Surface Temperatures (SST)
SST anomalies for several commonly-known ENSO regions
Outgoing Longwave Radiation (OLR)
This OLR product is a proxy for convective precipitation in the western equatorial Pacific
Sea Level Anomalies
Sea surface height images from the Jason-3 satellite
TAO/Triton Data Display
Surface marine data from an array of moored buoys
