With fall slowly creeping up, experts are warning of a record strong El Niño, colloquially dubbed “super El Niño.” The weather event is expected to impact global temperatures and rainfall, and could increase the risk of extreme weather events in some parts of the world.
What is El Niño?
El Niño, and its opposite La Niña, are climate patterns that naturally occur in the tropical Pacific. El Niño years tend to see warmer than average waters in the central and eastern Pacific Ocean, while La Niña years are associated with colder than average water temperatures.
The corresponding weather events triggered by the warmer ocean can have a varied and strong impact around the globe. With El Niño, forecasters are expecting to see stormier weather in some parts of the world and drought conditions in others.
“Pacific sea surface temperatures are going to vary at least two degrees from the average. That means the Pacific waters are going to be warmer than normal, and we can expect a lot of evaporation,” says Risper Nyairo, assistant professor in the department of environmental studies at Davidson College. That evaporation means more moisture in the sky in some areas which can lead to more rain. Meanwhile evaporation over dry land can increase drought.
El Niño typically peaks in the last few months of the year, but will remain active in the beginning of 2027. Forecasts are predicting that this year’s El Niño will be the strongest in recorded history. “The ocean conditions in the tropical Pacific are pushing towards record warmth,” says Marty Ralph, director of the Center for Western Weather and Water Extremes, and research meteorologist at UC San Diego Scripps Institution of Oceanography.
The warmer oceans, coupled with already record warming due to climate change, means that 2027 could shape up to be the warmest year on record. The World Meteorological Organization has also warned that a strong El Niño could raise the risk of extreme weather events going into next year.
Australia, Indonesia, and parts of Southern Africa, including Zambia and Zimbabwe, are likely to see drier than average conditions. Parts of South America, including Ecuador, Peru, and Uruguay, and East African countries will experience more rainfall than usual.
What does El Niño mean for fall and winter weather in the U.S.?
U.S. residents don’t have to sound the alarm over El Niño, says Patrick Rafter, assistant professor in the College of Marine Science at USF. “For the most part, I don’t see a monster El Niño event as anything the continental U.S. has to be overly concerned with.”
Historically, El Niño often brings a warmer than usual winter to the northern U.S., and a wetter, cooler winter in the south, with a higher likelihood for rain and snow. It can also increase the likelihood of tornadoes in areas receiving wetter weather.
“We will likely see less severe or less frequent hurricanes, but probably more severe tornadoes with severe storms,” says Nyairo.
El Niño years are typically associated with quieter hurricane years off the Atlantic. This year, the Atlantic hurricane season reached its peak without a single storm. The Pacific, however, has seen an unusually active hurricane season.
Along the west coast, El Niño could bring bigger waves and higher sea levels. The weather event also creates a higher risk of wildfires in areas with dry conditions.
The predictions, experts note, are just that. “There tend to be patterns that generally occur, but they aren’t always guaranteed outcomes,” says Ralph. The Indian Ocean Dipole, which impacts sea surface temperatures in the Indian Ocean, and the Madden-Julian Oscillation, a tropical atmospheric phenomenon that influences rainfall, are among some of the other modes of climate variability that can also impact weather patterns alongside El Niño.
Atmospheric rivers, narrow regions of the atmosphere that can carry moisture thousands of miles, can also disrupt El Niño conditions—particularl in California, where they often occur.
“We’ve seen since 2000 roughly that some of the El Niño years when we expect it to be relatively dry down in SoCal, it’s ended up being unusually wet,” says Ralph.
Regardless, a strong El Niño has the potential to have long lasting impacts for communities around the world. “The increased rainfall or intense drought cascades into other impacts on society,” says Nyairo. “Lives may be lost in unprepared societies. There could be property damage. There could be other related natural hazards… There’s a myriad of impacts.”
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