A “super” El Niño now has a 95% chance of developing this year as the climate pattern gains dramatic strength in the Pacific Ocean — leaving officials across California and beyond bracing for a wet and potentially destructive winter.
The National Oceanic and Atmospheric Administration’s Climate Prediction Center said Thursday that the El Niño has strengthened in the last month, and there’s a roughly 7 in 10 chance it will be the strongest such pattern since 1950.
Of the three other powerful El Niños on record during that span — in 1982-83, 1997-98 and 2015-16 — two brought above-average rain to Southern California. The 2015-16 El Niño, while very strong in the ocean, did not, though the pattern was blamed for record beach erosion along the California coast.
El Niño is a climate pattern characterized by warmer ocean waters in the central and eastern tropical Pacific, coupled with changing atmospheric conditions, in which the typical east-to-west trade winds weaken or even reverse.
That shift can put Southern California in the crosshairs of potentially potent tropical moisture, though the pattern’s effects vary by area.
If El Niño behaves like it typically does, Southern California would expect above-average precipitation, generally from cold-frontal storms that dip farther south than usual, according to Alexander Gershunov, research meteorologist at the Scripps Institution of Oceanography at UC San Diego.
“The forecast has been evolving over the last few months, and is honing in on a strong El Niño, and possibly an unprecedented one,” Gershunov said. “We may already be seeing some of the impacts from El Niño, because even though it’s a regional pattern in the central and eastern tropical Pacific, it’s such a huge area that warms up during El Niño that it adds a lot of heat to the global climate system.”
Added to the trend caused by human-caused global warming, “we’re basically on track to set a new global temperature record this year,” Gershunov said. “We’ve all been feeling the heat that’s associated with that.”
The average global surface temperature in July was among the hottest for that month in the modern record, which stretches back to 1850, tying the record from July 2024, according to NOAA’s National Centers for Environmental Information.
Looking forward, parts of coastal California have a higher-than-50% chance of above-average temperatures for August, the NCEI said.
Among the risks El Niño poses to California are stronger-than-usual hurricane activity in the eastern Pacific, which has sent hazardous and at times deadly high waves to the state’s shores. The last El Niño, over the 2023-24 season, coincided with the northward march of Hurricane Hilary toward Southern California — though that system had officially degenerated into a post-tropical low by the time it reached the state, officials said months later.
The risk for Southern California from an arriving tropical storm is not so much strong winds, but “just a lot of tropical moisture that leads to torrential rains. This year, it’s more likely that the tropical storm may make it out here intact. But it’s still a very low-probability event,” Gershunov said.
In the modern historical record, past El Niños have never been warmer than 4.5 degrees above baseline. But there is now a 69% chance that this El Niño will reach or exceed that threshold in the tropical Pacific.
That “has never happened in our historical record dating back to 1950,” Michelle L’Heureux, the El Niño team lead for the Climate Prediction Center, told The Times.
The last record set was during the 1982-83 El Niño season, where the Relative Oceanic Niño Index was 4.32 degrees above baseline.
The most potent type of El Niño is officially designated as “very strong,” though it’s often referred to as a “super” El Niño. Reaching that threshold requires temperatures in the equatorial Pacific to be at least 3.6 degrees above baseline.
For the three-month period of October, November and December, NOAA’s Climate Prediction Center forecasts a 95% chance that El Niño will be “very strong” and a 5% chance it will merely be “strong.”
Historically, the effects of El Niño on Southern California’s rainfall and snowfall become more obvious from December onward, with January to March “as the prime season for impacts,” L’Heureux said.
So far, there’s no conclusive evidence that El Niño is affecting the West Coast, NOAA research oceanographer Michael Jacox told The Times. The California coast is, however, being affected by a marine heat wave that isn’t currently related to El Niño, especially in Southern California, which experts say is a factor in the mugginess being felt along some coastal areas.
However, Gershunov noted that elevated hurricane activity in the eastern Pacific is likely related to El Niño, which other meteorologists say has also contributed to the feeling of humidity in Southern California.
“We are into the time of year now when El Niño’s impacts could be felt any time; this initial impact should be due to coastal trapped waves coming from the south,” Jacox said.
When looking at July alone, ocean temperatures in the equatorial Pacific are the second-highest for the month on record, according to L’Heureux. Temperatures in the area of the ocean used to calculate El Niño were already 2.41 degrees above baseline.
The only July in modern times where that reading was stronger was in 1997, when the ocean temperatures there were 2.74 degrees above the baseline.
El Nino’s effects have already been noticed in other parts of the world. The Indian monsoon season arrived late, a factor in the tremendous heat waves that have hit India, Gershunov said.
