What El Niño Means for Fall and Winter Weather in the U.S.

As fall arrives, weather scientists are sounding the alarm about a powerful El Niño that could break all records. El Niño is a natural weather pattern in the Pacific Ocean that affects temperatures and rainfall around the world. Experts say this event could bring unusual storms, droughts, and extreme weather to many countries. In the United States, it may change what fall and winter look like this year and into early 2027.

El Niño happens when the water in the central and eastern Pacific Ocean gets warmer than normal. Its opposite, La Niña, brings cooler water temperatures to the same area. These changes in ocean temperature can cause big shifts in weather all over the globe. When the water is warmer, more of it evaporates, putting extra moisture into the air. That extra moisture can bring heavy rain to some places and drought to others.

Scientists say that this year the Pacific Ocean is at least two degrees warmer than usual. Risper Nyairo, a professor who studies the environment at Davidson College, explains that warmer water means more evaporation. More evaporation means more rain in some areas. But in dry places, that same evaporation can make droughts even worse.

Experts predict that this El Niño will be the strongest in recorded history. Marty Ralph, a meteorologist at UC San Diego, says that ocean conditions in the tropical Pacific are pushing toward record warmth. El Niño usually peaks near the end of the year, but this one is expected to stay active into early 2027. Combined with warming already caused by climate change, 2027 could become the hottest year ever recorded.

Not every country will be affected the same way. Countries like Australia, Indonesia, Zambia, and Zimbabwe are likely to get drier than normal conditions. On the other hand, parts of South America and countries in East Africa could see much more rainfall than usual. These differences show how one weather event can have very different effects depending on where you live.

For people living in the United States, experts say there is no need to panic. Patrick Rafter, a professor at the University of South Florida, says the continental U.S. does not need to be overly worried. However, El Niño does tend to bring noticeable changes. The northern part of the country usually sees a warmer winter than normal, while the south tends to get a wetter and cooler winter.

El Niño can also affect dangerous weather events like hurricanes and tornadoes. In years with El Niño, the Atlantic hurricane season is usually quieter. In fact, this year's Atlantic hurricane season reached its peak without a single storm forming. However, Nyairo warns that while hurricanes may be less common, tornadoes could become more severe in areas that get extra rain and storms.

Along the West Coast, El Niño could bring bigger ocean waves and higher sea levels. Dry areas may face a greater risk of wildfires. California, in particular, could also be hit by atmospheric rivers — narrow bands of moisture that can carry water thousands of miles. These have sometimes made California much wetter than El Niño predictions suggested.

It is important to remember that weather predictions are not guaranteed. Ralph notes that patterns generally occur, but they are not always certain outcomes. Other climate events, like the Indian Ocean Dipole and the Madden-Julian Oscillation, can also affect weather alongside El Niño. Together, these forces make weather forecasting very complicated.

Even so, a strong El Niño can have serious, long-lasting effects on communities. Heavy rainfall can cause flooding, and intense drought can destroy crops and water supplies. Nyairo points out that these impacts can hurt people's lives, damage property, and trigger other natural hazards. Communities that are not prepared for these changes are most at risk.