Forecasters predict that an El Niño winter is highly likely to occur, with a greater than 95% chance of it continuing through the Northern Hemisphere winter. The chance of a strong El Niño has also increased. Last winter, the Chicago area experienced an unusually high amount of rain and warmer temperatures, and the latest forecast suggests that this could happen again. However, forecasters emphasize that every El Niño event is unique, and the impacts can vary from one event to another.
El Niño refers to a period when sea-surface temperatures in the Pacific Ocean, particularly near the equator, are warmer than usual. This change in water temperatures affects weather patterns around the world. Normally, trade winds blow warm water from South America towards Asia, but during El Niño, these winds weaken and the warm water is pushed back east. The specific impacts of El Niño on weather conditions depend on its size, intensity, and duration.
In general, an El Niño year can lead to drier and warmer conditions in the northern US and Canada, while the Gulf Coast and Southeast may experience wetter conditions and an increased risk of flooding. The impact of El Niño on the Chicago area varies, but previous events have resulted in cooler and wetter summers, wetter and cooler falls, warmer and drier winters, drier springs, below-average snowfall, and lower heating bills. The latest projections for the coming winter in Chicago suggest that residents can expect warmer-than-normal temperatures and below-normal precipitation. These projections extend into March as well.