7 Day Forecast
Weeks after the Pacific Ocean engine that helps drive the world's weather shifted into neutral, meteorologists and scientists are now laser-focused on the developing signals of its warm phase — El Niño.
It's what the global forecast models are making of the early signals that is drawing attention.
Virtually all of the models show an El Niño forming in the weeks ahead, and the median estimate across them is for "quite a strong event," said Zeke Hausfather, director of climate and energy at the Breakthrough Institute and a research scientist with Berkeley Earth. "This would put us on track to have an event that is among the strongest El Niños seen in recent history, though it is too early to know with much certainty."
The prospect of a strong El Niño raises fears of additional heat, given its expected arrival at a time when temperatures already have been warmer-than-normal in much of the West and over parts of the Pacific for months. The forecasts raise alarms globally because of the pattern's powerful influence over the world's weather, and a strong event could create rippling impacts that last for months to come.
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Previous El Niños fueled wildfires, caused extreme flooding and mega droughts, prompted widespread coral bleaching and disrupted marine life migrations and foraging.
A blanket of smoke fills the air from Canadian wildfires moving south in downtown Milwaukee on July 31, 2025.
What is El Niño?
The natural, recurring pattern in the central and eastern Pacific Ocean cycles between three phases: El Niño, La Niña and neutral. First documented by fishermen off the west coast of South America in the 1600s because it brought unusually warm water to the eastern Pacific around Christmastime, its impacts extend far beyond that coast.
Disturbances over the Pacific Ocean have such a far-reaching potential for impact because the ocean is so large. It influences where ocean heat is released into the atmosphere, affects atmospheric circulation, temperatures and precipitation around the world.
The National Oceanic and Atmospheric Administration once said that to the rest of the global atmosphere, "the arrival of El Niño in the Pacific is like a giant ringing a bell so loudly that it knocks the dishes off the shelves in a house down the street."
La Niña is gone, but its effects linger as scientists watch for El Niño and the possible return of “the Blob” ocean heat wave.
How strong could El Niño be?
While the forecasters and the global models see factors such as an extending plume of warm water in the Pacific that suggest odds are increasing for a strong El Niño, the potential strength of the event remains to be seen.
The eventual outcome is dependent on the wind patterns along the equator in the Pacific over the summer, NOAA said in April.
Several factors are in play. First, the computer models have better skill between June and December than earlier in the year, according to the Columbia Climate School at Columbia University. So as the summer progresses, the forecasts are likely to have better accuracy.
Other surrounding weather patterns moving through the atmosphere also can affect El Niño formation and strength. And this year NOAA started using an adjusted index that accounts for the warmer temperatures from climate change before calculating strength, Hausfather said. The method has been debated, but he said it's arguably a better way to remove the effects of "human-driven global warming" so that it doesn't make it appear that El Niños are getting stronger over time.
Does every El Niño act the same?
Three previous El Niños are considered the most intense: 1982-1983, 1986-1987 and 2015-2016. They were blamed for weather disasters around the world, including floods, extreme droughts and famines in Africa, increased cases of mosquito-borne viruses on the East Coast and a large "blob" of ocean water in the Pacific that killed roughly a million seabirds.
Do previous El Niños demonstrate what we'll see later this year? Not necessarily. Years ago, NOAA scientist Deke Arndt humorously explained this in a 2015 blog post for the agency's former website Climate.gov.
In your favorite establishment, the staff might bring you your signature beverage when you walk in. But one night you could walk in and the bartender hands you something completely unexpected, wrote Arndt, now director of the agency's National Centers for Environmental Information.
"El Niño is like that bartender," he wrote. Seeing the bartender might tilt your odds toward getting your favorite beverage, but it’s not a guarantee. "In other words, sometimes El Niño is the bartender who doesn’t bring you what you ordered."
