The Climate Prediction Center says El Niño is now “very strong” after its latest weekly Relative Oceanic Niño Index reading topped 2°C, calling it likely a historic intraseasonal event. Niño 3.4 was 2.1°C above average, up from 2.0°C on Sept. 17.
The CPC’s Sept. 17 winter outlook favors warmer-than-normal temperatures across much of the West and the northern and central U.S. east of the Rockies. It gives 50–60% odds of a wetter-than-normal winter near the California coast and 70–80% in southern Georgia and northern Florida, while the interior Northwest and Great Lakes lean slightly drier. The CPC said California’s odds could rise in October, with the wet zone potentially extending to central Oregon or farther north.
In its Sept. 10 discussion, the CPC put the chance of a very strong event this fall and winter above 90%, and the chance of a historic event from October through December at 75%, defining historic as a three-month RONI of at least 2.5°C. It said El Niño impacts are more likely with an event of this magnitude, but not guaranteed. The CPC expects the event to strengthen through year-end and persist into spring 2027; its next monthly discussion is due Oct. 8, and NOAA’s official winter outlook is scheduled for Oct. 15.
