The US National Weather Service released an advisory on Thursday stating that risks of a historic El Niño event are rising. Forecast models indicate an 81% chance that a very strong El Niño will develop before the end of the year.

There is a 97% probability that El Niño conditions will persist through spring 2027. Climate scientist Daniel Swain said, "The odds and the magnitudes just keep rising."

Swain stated, "El Niño so far, for the calendar date, is as strong or stronger than we've ever seen before, and that is a trajectory that is expected to continue." An El Niño is classified as a super El Niño if it drives sea surface temperatures at least 2C (36F) higher than average.

Last week, a heat dome caused temperatures above 100F (38C) in twenty US states. This event resulted in at least dozens of deaths and millions of emergency room visits in the US.

Firefighters battled 38 large wildfires across the US on Thursday. More than 3.4 million acres (1.4 million hectares) have burned in the US this year. Swain indicated that "By Sunday and Monday, we start to see some eyebrow-raising temperatures."

Why It Matters

The potential for a historic El Niño event, as indicated by the 81% chance of a very strong development and 97% probability of persistence through spring 2027, suggests prolonged weather pattern shifts. This event follows a period where parts of the US experienced extreme weather, including 100F (38C) temperatures and 38 large wildfires. The forecast trajectory toward a potentially record-strong El Niño could influence future weather conditions across the US, building on existing climate stressors already observed this year such as extensive wildfires and heat-related health impacts.