The National Weather Service announced Thursday that El Niño season has begun and that models show the event could be very strong.
Ariel Cohen, a meteorologist for the NWS in Los Angeles, said, “There is a 63% chance that we’re looking at a very strong El Niño during the November to January time period that could rank amongst the largest El Niño events in the historical record.” He added, “We’re already seeing those warm temperatures lining up” at a news conference held by the Aquarium of the Pacific in Long Beach, California.
El Niño is a natural climate pattern that causes warm surface temperatures in the tropical Pacific Ocean and is associated with higher average global temperatures, which the article said exacerbates warming from climate change.
The pattern is linked to fewer hurricanes in the Atlantic and more in the Pacific and, in the U.S., typically shifts the jet stream in winter, pushing it south and altering regional weather patterns.
That shift typically brings dry, warmer-than-usual winter conditions to the Pacific Northwest, which the article said is already mired in drought after receiving middling snow, while Southern states typically see unusually wet winter weather that could prime the region for flooding.
Andrew Leising, a research oceanographer with the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center, said two marine heat waves are already affecting the Pacific, one near the coast of California and another farther offshore, and that El Niño is expected to drive temperatures in the Pacific up even more this fall. “One of the most important things for the animals in the ecosystem is not necessarily just how hot it is ... but just how long they’re exposed to the heat,” Leising said.
The article cited past impacts from extended marine heat waves, noting that in 2015 an extreme event nicknamed “The Blob” pushed ocean temperatures about 7 degrees Fahrenheit above normal, contributed to die-offs of seals, sea lions, baleen whales and seabirds, and closed West Coast Dungeness crab, sea urchin and salmon fisheries worth millions of dollars while producing large blooms of pyrosomes that clogged fishing nets.
“This may bring unusual visitors,” Nate Jarros, vice president for animal care at the Aquarium of the Pacific, said, listing yellowfin tuna, mahi-mahi, yellow-bellied sea snakes, seahorses and whale sharks as species that have appeared during past El Niño events. He added, “Warm waters are attractive to some species of sharks, including makos, blues and white sharks, and this warming trend can expand the range of many species further north.”
The article noted that although El Niño generally raises global temperatures, climate change is the primary driver of recent record warmth, and said that 2024 was the hottest year on record, about 2.65 degrees Fahrenheit (1.47 degrees Celsius) warmer than the average from the mid-19th century, according to NASA, while 2025 was the third-hottest year on record. It added that worldwide the past 11 years have been the 11 hottest ever recorded.