El Niño is the naturally occurring warm phase of the El Niño-Southern Oscillation (ENSO), a climate pattern in the Pacific Ocean. During El Niño events, sea surface temperatures in the central and eastern Pacific Ocean near the equator become warmer than average.

NOAA and other scientific agencies are forecasting the current El Niño to become very strong over the next 2–9 months—perhaps the strongest in over 150 years. An El Niño is classified as “very strong” when sea surface temperatures in the eastern tropical Pacific consistently exceed 2°C above average for several months. In July 2026, ocean temperatures in this region were 2°C to more than 3°C above normal, and additional warming is expected through autumn and early winter.  

The 2026 El Niño is raising important questions for resource management across the country. To support planning and decision‑making, the Climate Adaptation Science Centers have developed a series of webpages that outline the forecasted regional impacts of the 2026 El Niño and discuss what these changes may mean for resource management in each CASC region. The webpages offer a high level overview of El Niño, followed by a closer look at potential shifts in temperature, precipitation, storms, and more in each region of the U.S., along with what those changes could mean for resource management.