El Niño got stronger again in October, and NOAA now puts the chance of a strong to very strong event lasting through early spring at better than 79%. The monthly update from NOAA's Climate Prediction Center, issued Thursday, Nov. 12, keeps the El Niño Advisory in place and says the event should keep strengthening for a little longer before it starts to weaken in early 2027.
The odds of a record-setting El Niño have come down, though. Last month forecasters gave an 83% chance that October through December would beat every El Niño on record since 1950. Thursday's update puts that chance at about 60%, for both October to December and November to January. That is still better than even.
What changed in the Pacific
Ocean temperatures along the equator are the main gauge, and they rose across the board in October.
| Measure | September (Oct. 8 update) | October (Nov. 12 update) |
|---|---|---|
| Niño-3.4, the main El Niño index | +2.1°C | +2.5°C |
| Niño-3, eastern Pacific | +3.0°C | +3.6°C |
| Niño-1+2, off South America | +3.9°C | +4.4°C |
| Chance of strong to very strong El Niño through Jan.-Mar. 2027 | above 83% | above 79% |
| Chance of a record event, Oct.-Dec. | 83% | about 60% |
Surface water in parts of the eastern Pacific ran more than 4°C above normal, and that warm patch spread farther west than it did a month earlier. Below the surface, some readings in the eastern Pacific were more than 10°C above average. The atmosphere is following along. The usual east-to-west trade winds near the surface are weaker than normal across much of the equatorial Pacific, rain and thunderstorms stayed heavier than normal from the central to the eastern Pacific, and storm activity over Indonesia remained suppressed.
What it means for the winter
NOAA's forecast has El Niño peaking around November to January and fading through the spring. Its central forecast brings the main index back near zero by May to July 2027.
A very strong El Niño makes the winter weather usually linked to it more likely, the update says, "though not guaranteed." The Climate Prediction Center's seasonal outlooks give the odds for each region.
For the next few weeks, NOAA still favors a mild late November for most of the country, as Edit USA reported on Nov. 6, even with an unusually early disruption of the polar vortex over the Arctic.
The next monthly El Niño update is scheduled for Thursday, Dec. 10.
