El Niño in the Pacific is producing chart-topping heat data. Its effects are predicted to spread across the globe.
Can scientists still really trust El Niño forecasts?
Scientists have warned that while El Niño reduces the likelihood of hurricanes, storms can still form because the ocean stores excess heat.
Sea surface temperatures in the Pacific Ocean have exceeded daily warming records for more than 20 days in June, a precursor to what many scientists predict will be one of the strongest El Niño events on record.
Ocean temperatures in the El Niño region along the equator in the central and eastern Pacific are not just warmer than normal. It’s warmer than on record for this time of year and almost the hottest at any time of the year.
The effects are expected to reverberate across the planet, changing weather patterns for months to come. For some people, it will increase the risk of damaging extreme weather events such as tornadoes, winter storms, and back-to-back storms that can cause flooding and landslides. For other regions, there could be beneficial rain and fewer tropical storms and hurricanes. Either way, El Niño will continue to be a big topic throughout 2026.
Kevin Trenberth, a climate scientist at the National Center for Atmospheric Research, said El Niño is well underway. The upper ocean temperature in this region is more than 3 degrees higher than normal.
The National Oceanic and Atmospheric Administration and others predict El Niño’s peak will occur between November and January, but its effects could last until 2027.
Here are five things you need to know about why experts say this event could become such a big deal.
El Niño changes global weather patterns
Daniel Swain, a climate scientist at the University of California’s College of Agriculture and Natural Resources, said on the June 17 WeatherWest podcast that El Niño, a naturally occurring climate cycle, is already having an impact along the equator.
As waters warm in El Niño regions, their patterns link with the atmosphere, causing changes in trade winds, jet streams, and other global weather systems.
Emily Becker, a research professor at the NOAA Oceanic and Atmospheric Research Institute at the University of Miami, said rainfall patterns could change, causing large areas to become drier or wetter.
El Niño isn’t just a random movement of warm water in the ocean. Trenberth said it “plays an important role in moderating temperatures in the tropical Pacific Ocean.” The warm water that accumulates in the Pacific Ocean moves toward higher latitudes in the ocean, where the thermal energy is released into the atmosphere as precipitation.
Record-breaking heat is just one element of El Niño to worry about
Scientists who track upper ocean temperatures in the El Niño region predict that this pattern could cause a temporary increase in global temperatures, making either 2026 or 2027 the warmest year on record.
Meanwhile, in California, El Niño is increasing the risk of what Swain calls an “arc storm,” an extreme flooding scenario — an onslaught of rain repeated over three to four weeks.
Becker said Indonesia is at high risk of wildfires and temperatures tend to fluctuate “significantly” around the Galapagos Islands, which are rich in biological resources. These changes could reduce the upwelling of cold, nutrient-rich water and have “severe implications” for marine life from anchovies to penguins. El Niño is also thought to be historically responsible for large-scale coral bleaching.
Although El Niño is often seen as a global catastrophe, it can also have positive effects, Becker said. In regions such as the southeastern United States, which currently suffers from severe drought and wildfires, El Niño could replenish groundwater and alleviate drought conditions. It is also known to help reduce the number of Atlantic hurricanes.
A June 16 report from CropMonitor.org explained how El Niño has a variety of impacts on agricultural production. While some regions of the world may see negative impacts, other regions, including the United States, have historically seen more positive impacts.
“There is no question that it could have a devastating impact on some parts of the world in terms of flooding and drought,” Becker said. But unlike catastrophic events that come suddenly without warning, scientists know in advance that El Niño is coming.
It’s an “opportunity to prepare,” she says. “Disasters will occur all over the world, but El Niño gives us the opportunity to understand when and where they will occur.”
El Niño patterns can be unpredictable
El Niño increases the probability of certain extreme weather events, but does not guarantee them.
For reasons that are not yet fully understood, the outcome may differ from previous events. For example, extreme rainfall events caused widespread flooding and landslides in California during the 1982-1983 and 1997-1998 El Niño periods, but not during the 2015-2016 El Niño period, Swain said. Just because you’re “leaning a little” towards a wet pattern doesn’t prevent you from getting a dry result.
“It’s like baking a cake,” said Antonietta Capotondi, a scientist at the University of Colorado Boulder Cooperative Institute for Environmental Sciences. “We need all the ingredients, but we also need a functioning oven for predictable results. We have the main ingredients. As long as the oven doesn’t break, we should be able to make a cake.”
El Niño adds to existing problems
The effects of El Niño occur in addition to other meteorological and climatic phenomena, such as global warming, sea level rise, and astronomical storm surges. For example, the El Niño region’s temperature increase occurs in the context of warmer-than-normal temperatures across vast areas of the Pacific Ocean. Scientists say El Niño is already causing sea levels in the Pacific Ocean to rise as the ocean warms and expands.
Along the California coast, where climate change is causing sea levels to rise 6 to 12 inches in some places, El Niño could temporarily cause sea levels to rise more than 6 inches, Swain said. Rising sea levels, combined with natural tide rises during full moons and winter storms, will cause more localized coastal flooding.
Scientists continue to study the extent to which rising temperatures will affect the traditional effects of El Niño.
Trenberth said there is clear evidence that some of the connections between larger weather patterns in the atmosphere are being altered by climate change. For example, jet streams and storm trajectories “shifted poleward over oceans in both hemispheres.”
This El Niño may be unusually strong.
Climate scientists expect El Niño to be strong, but model predictions differ on how strong it will be. Strong or very strong El Niño events tend to have more severe impacts than weak ones.
“We are confident that a strong El Niño will occur this year,” Becker said.
Based on model predictions, this could be the fifth-strongest since 1982, when satellites began tracking ocean temperatures, said Chris Karnauskas, a scientist at the Cooperative Institute in Boulder and Capotondi’s colleague.
“The fuel for a major El Niño is there,” Karnauskas said recently. “The question is, does that heat bubble up to the surface, or does it stay hidden beneath the surface?”
Swain believes there is “substantial and growing evidence” of a potentially record-breaking El Niño event.
If the El Niño phenomenon strengthens, it could have a significant impact on the global economy. Global income losses due to the El Niño events of 1982-1983 and 1997-1998 are estimated to be in the trillions of dollars.
Current projections suggest that the 2026-2027 El Niño could be the most damaging yet, according to research by Justin Mankin, an associate professor of geography at Dartmouth.
Contributor: Doyle Rice, USA TODAY
Dinah Boyles Pulver, a national correspondent for USA TODAY, covers climate change, weather, the environment and other news. Contact dpulver@usatoday.com or @dinahvp on Bluesky or dinahvp.77 on X or Signal.
