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, including marine heat waves, piling on top of long-term climate warming 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 are raising alarms globally because of the pattern’s powerful influence over the world’s weather, and a strong event could create ripple effects for months to come.
El Niños have fueled wildfires and caused extreme flooding and megadroughts. They have prompted widespread coral bleaching and disrupted marine life migrations and foraging.
Uncertainty remains, however. Spring is a notoriously tricky time for El Niño models.
In its April update, the National Oceanic and Atmospheric Administration put the chances of a strong El Niño at 1 in 4. Since then, ocean surface temperatures have been climbing in the El Niño region. NOAA’s next update comes May 14.
What is El Niño?
The El Niño-Southern Oscillation is “arguably the most influential climate driver on Earth,” according to the Cooperative Institute for Research in Environmental Sciences at the University of Colorado, Boulder.
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 effects extend far beyond that coast.
Disturbances over the Pacific Ocean can have far-reaching consequences because the ocean is so large. It influences where ocean heat is released into the atmosphere, atmospheric circulation, temperatures and precipitation around the world.
NOAA 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.”
What’s happening right now?
The cooler phase – La Niña – faded into the sunset in early April, and though its influence on drought in parts of the United States may linger, El Niño is widely forecast to begin in the weeks ahead. Satellite data shows sea surface temperatures rose sharply in April in the central and eastern Pacific.
But it takes more than just warmer-than-normal waters to meet the threshold NOAA uses to declare an El Niño. It takes water nearly a full degree warmer than average in the El Niño region over a period of time, with a corresponding weakening of the trade winds and response in the atmosphere.
The West and Southwest regions of the country saw their warmest winters on record. The northeast Pacific reached its highest ever average temperature, about 69 degrees, on Sept. 9, and marine heat waves continued through the winter and into the spring, according to NOAA. In March, ocean waters along parts of the West coast were roughly 3 to 4 degrees above normal based on NOAA’s latest sea surface temperature measurements.
And on March 8, NOAA said the past 12 months in the Lower 48 were again warmer than any other 12-month period, and severe to exceptional drought is occurring over 40% of the continental United States.
How strong could El Niño be?
Though forecasters and 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.
Like Hausfather, Brian McNoldy, a senior research associate at the University of Miami, is among those who maintain websites with regular updates on the global forecast models. McNoldy also offered a word of caution in a recent social post.
“There is lots of chatter about the forecast development of a strong #ElNiño,” McNoldy said. The models “are in very good agreement on that. But the consensus is an ‘average’ strong El Niño, not historic.”
The eventual outcome depends on wind patterns along the equator in the Pacific over the summer, NOAA said in April.
Several factors are in play. First, 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 be more accurate.
Double danger? Climate change, El Niño push Earth ‘beyond its limits’
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 El Niños have been considered the most intense: 1982-1983, 1986-1987 and 2015-2016. They’ve been 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 1 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.”
Hurricanes and El Niño
One notable effect of El Niño is a tendency to decrease tropical activity in the Atlantic Ocean. A shift in the path of the jet stream over the United States can spawn downdrafts and sinking winds that have been known to suppress – but not eliminate – hurricane activity in the main region of the Atlantic where hurricanes often form. Those winds can prevent storms from building the self-sustaining structure they need to become hurricanes.
But the National Hurricane Center and others warn that storms, even major devastating hurricanes, can and do occur in El Niño years, particularly in the Gulf of America, formerly the Gulf of Mexico. When comparing 15 of the warmer El Niños on record, at least 37 named storms have made landfall in the contiguous United States, including 14 hurricanes.
La Niña and wildfires
Even as conditions shift, researchers warn lingering effects from La Niña can still contribute to increased wildfire activity.
A study by the Cooperative Institute and NOAA researchers found a strong link between fall La Niñas and an increase in spring fire activity. It reported a twofold increase in the relative risk of extensive burns in the South, Southwest and Rocky Mountains, as well as risks in the Great Basin and Northern California regions during summer. An autumn El Niño appears to elevate the risk of large fires in the eastern and northern Rocky Mountains in the spring.
The El Niño oscillation “offers a powerful tool for predicting the likelihood of extensive wildfire activity in several U.S. regions up to a year out,” said Andrew Hoell, a NOAA researcher and lead author of the study published in the Journal of Geophysical Research: Atmospheres.
As the vast Pacific engine begins to shift again, scientists will be watching the satellites and other instruments to determine how the world’s weather will change in the months ahead.
See NOAA’s projected sea surface temperature anomalies
Click the buttons at the top of the chart labeled SST anomaly and outlook to see the projections over the next 16 weeks.
Sea surface temperature anomaly outlook
Dinah Voyles Pulver, a national correspondent for USA TODAY, writes about violent weather, climate change and other news. Reach her at dpulver@usatoday.com or @dinahvp on Bluesky or X or dinahvp.77 on Signal.
This article originally appeared on USA TODAY: El Niño forecast in 2026. Here’s what it means for heat, hurricanes
