US forecasters say the El Niño climate pattern is strengthening and is highly likely to become one of the largest events recorded. In an updated assessment, the US Climate Prediction Center (CPC) reports an 81% chance that El Niño will reach “very strong” strength between October and December, when it is expected to peak. The CPC defines “very strong” as at least 2.0°C above a reference index. Forecasts also indicate a 97% likelihood the event will persist through early spring 2027.

The strengthening is tied to warming in parts of the equatorial Pacific, with sea surface temperatures currently about 1.2°C above average in the Niño 3.4 region, alongside changes in winds and atmospheric pressure that reflect a more active ocean–atmosphere system. The reports note that El Niño typically peaks in late year, and the highest temperature signal often arrives later.

Sources also highlight potential global impacts commonly associated with El Niño, including drought risk in some regions such as parts of Australia and the southern United States, and wetter conditions in areas such as East Africa and parts of the southern United States. Experts cited also point to the influence of long-term warming, which may increase the likelihood of stronger events.