Just weeks after the Pacific engine that helps drive the world’s weather shifted to neutral, meteorologists and scientists are now focusing on the developing signal of its warm phase: El Niño.
The analysis of early signals by global forecast models has attracted attention.
Zeke Hausfather, director of climate and energy at the Breakthrough Institute and a Berkeley Earth research scientist, said nearly all models show El Niño will develop in the coming weeks, with the median estimate from those models calling for a “pretty strong event.” “This would put us on track for one of the strongest El Niños in recent history, although it’s too early to know for sure.”
The prospect of a strong El Niño has raised concerns about additional heat, including marine heat waves, adding to long-term climate warming, as it is expected to arrive at a time when much of the West and parts of the Pacific have already been warmer than normal for months. The forecasts set off alarm bells around the world due to the pattern’s powerful influence on the world’s weather, and a strong event could have ripple effects for months to come.
El Niño fuels wildfires and causes severe flooding and extreme droughts. They cause widespread coral bleaching and disrupt the migration and feeding of marine life.
However, uncertainty remains. Spring is a notoriously tricky time for El Niño models.
In its April update, NOAA put the chance of a strong El Niño at 1 in 4. Since then, sea surface temperatures have been climbing in El Niño regions. NOAA’s next update will be released on May 14.
A May 6 satellite image from the National Oceanic and Atmospheric Administration shows areas of the world’s oceans where surface water temperatures are warmer or colder than normal. The orange and red developing patterns along the equator in western South America show the conditions scientists expect will create an El Niño later this summer.
What is El Niño?
According to the Cooperative Institute for Environmental Science Research at the University of Colorado Boulder, the El Niño-Southern Oscillation is “arguably the most influential driver of climate on Earth.”
The natural circulation pattern in the central and eastern Pacific cycles between three phases: El Niño, La Niña, and neutral. The phenomenon was first recorded by fishermen on the west coast of South America in the 1600s, as it brought unusually warm waters to the eastern Pacific around Christmas, with effects far beyond that coast.
Because the Pacific Ocean is so large, disturbances in the Pacific can have far-reaching effects. It affects where ocean heat is released into the atmosphere, atmospheric circulation, temperatures and precipitation around the world.
The National Oceanic and Atmospheric Administration (NOAA) once said of the global atmosphere, “The arrival of El Niño in the Pacific is like a giant ringing a bell, so loud that it knocks the plates off the shelves of the houses on the street.”
What’s happening now?
The cooler phase – La Niña – faded into the sunset in early April, and while its impact on drought in parts of the United States is likely to linger, El Niño is widely forecast to begin in the coming weeks. Satellite data show that sea surface temperatures in the central and eastern Pacific Ocean rose sharply in April.
But to reach NOAA’s threshold for declaring an El Niño, warmer-than-normal water is not enough. For a period of time, water temperatures in El Niño areas can be nearly one degree above average, with correspondingly weaker trade winds and atmospheric responses.
The western and southwestern parts of the country experienced their warmest winter on record. On September 9, the Northeast Pacific reached its highest average temperature ever, about 69 degrees, and marine heat waves continued throughout the winter and into spring, according to NOAA. Sea temperatures in parts of the West Coast were about 3 to 4 degrees above normal in March, according to NOAA’s latest sea surface temperature measurements.
On March 8, NOAA said that the past 12 months have once again been warmer in the Lower 48 than any other 12-month period, and severe to abnormal drought is occurring in more than 40% of the continental United States.
How strong is El Niño?
While forecasters and global models believe factors such as the extension of warm Pacific water indicate an increasing likelihood of a strong El Niño, the potential intensity of the event remains to be seen.
Like Hausfather, University of Miami senior researcher Brian McNoldy is among those who maintain a website that regularly updates global forecast models. McNoldy also issued a warning in a recent social post.
“There’s a lot of discussion about the forecast development of a strong El Niño,” McNoldy said. The models “are very consistent on this point. But the consensus is for an ‘average’ strong El Niño, not a historic one.”
NOAA said in April that the final outcome depends on summer wind patterns along the equator in the Pacific Ocean.
Several factors are at play. First, computer models’ skill was better between June and December than earlier in the year, according to data from Columbia University’s Columbia Climate Institute. Therefore, forecasts are likely to become more accurate as the summer progresses.
Double jeopardy? Climate change, El Niño push Earth “beyond its limits”
Other surrounding weather patterns moving through the atmosphere also influence the formation and intensity of El Niño. This year, the National Oceanic and Atmospheric Administration began using an adjusted index that takes into account rising temperatures from climate change before calculating intensity, Hausfather said. The approach has been controversial, but he said it was arguably a better way to neutralize the effects of “human-induced global warming” so that it didn’t appear to be El Niño getting stronger over time.
Does every El Niño behave the same?
Three El Niños are considered the strongest: 1982-1983, 1986-1987 and 2015-2016. They have been blamed for weather disasters around the world, including floods, extreme droughts and famines in Africa; an increase in cases of mosquito-borne viruses on the East Coast; and a swath of water in the Pacific that killed an estimated 1 million seabirds.
Could previous El Niños be evidence of what we might see later this year? not necessarily. A few years ago, NOAA scientist Deke Arndt humorously explained this in a 2015 blog post for the agency’s former website, Climate.gov.
At your favorite venue, the staff may bring you your signature drink when you walk in. But one night you walk in and the bartender offers you something completely unexpected, writes Arndt, now director of the agency’s National Centers for Environmental Information.
“El Niño is like that bartender,” he wrote. Meeting the bartender may increase your chances of getting your favorite drink, but it’s not a guarantee. “In other words, sometimes El Niño is when the bartender doesn’t give you what you ordered.”
Hurricanes and El Niño
A significant effect of El Niño is the trend toward reduced activity in the Atlantic tropics. Changes in the path of the jet stream over the United States can create downdrafts and downdraft winds, which are known to suppress (but not eliminate) hurricane activity in major areas of the Atlantic where hurricanes often form. These winds can prevent storms from building the self-sustaining structures needed to become hurricanes.
But the National Hurricane Center and other agencies warn that storms, even severe and devastating hurricanes, can and do occur during El Niño years, particularly in the Gulf of America (formerly the Gulf of Mexico). Compared to the 15 warmer El Niños on record, at least 37 named storms have made landfall in the continental United States, including 14 hurricanes.
This Climate.gov infographic explains how El Niño Southern Oscillation affects global weather.
La Niña and wildfires
Researchers warn that even as conditions change, the lingering effects of La Niña could still lead to increased wildfire activity.
A study by researchers at the Cooperative Institute and the National Oceanic and Atmospheric Administration found a strong link between La Niña conditions in the fall and increased fire activity in the spring. The report said the relative risk of widespread burns doubled during the summer in the South, Southwest and Rockies, as well as in the Great Basin and Northern California. Fall El Niño conditions appear to increase the risk of spring fires in the eastern and northern Rockies.
Andrew Hoell, a researcher at the National Oceanic and Atmospheric Administration (NOAA) and lead author of the study published in the Journal of Geophysical Research: Atmospheres, said the El Niño oscillation phenomenon “provides a powerful tool for predicting the likelihood of large-scale wildfire activity in multiple regions of the United States over the course of a year.”
As the giant Pacific engine begins to shift again, scientists will be watching satellites and other instruments to determine how the world’s weather will change in the coming months.
Check out NOAA’s predicted sea surface temperature anomalies
Click the button labeled Sea Temperature Anomalies and Outlook at the top of the chart to see the forecast for the next 16 weeks.
Sea surface temperature anomaly outlook
Dinah Voyles Pulver is a national reporter for USA TODAY, writing about severe weather, climate change and other news. Contact her at dpulver@usatoday.com or @dinahvp on Bluesky or X on Signal or dinahvp.77.
This article originally appeared in USA TODAY: 2026 El Niño Forecasts. What this means for heat and hurricanes