Sonora, CA—A strengthening El Niño is expected to become one of the strongest such events on record this fall and winter, according to the National Weather Service.
The latest forecast gives El Niño a greater than 90% chance of reaching very strong levels during the Northern Hemisphere fall and winter of 2026-27. Forecasters also estimate a 69% chance that the event will reach a historic level between October and December, potentially exceeding the strength of previous El Niño events dating back to 1950. El Niño occurs when ocean waters in the tropical Pacific become unusually warm. That extra heat can alter the position of the jet stream, which in turn affects the path and strength of winter storms across the United States.
For California, El Niño is typically associated with wetter and cooler winters and an increased number of storms. Strong El Niño events can increase the chances of significant rain and mountain snow, although the pattern does not guarantee a wet winter or determine the weather on any particular day. The National Weather Service said ocean temperatures in the eastern tropical Pacific have continued to rise, while warmer water beneath the ocean’s surface has also increased. Atmospheric conditions have changed along with the warming ocean, providing further evidence that El Niño is strengthening.
The forecast calls for El Niño to continue strengthening through the end of 2026 and persist into early 2027. The National Oceanic and Atmospheric Administration notes that El Niño’s effects vary from one event to another. While the pattern can increase the likelihood of certain weather conditions, it cannot predict exactly how much rain or snow a particular location will receive.
The next National Weather Service El Niño update is scheduled for September 10th.
