Central Illinois, including Champaign-Urbana, is set to experience a colder, wetter than normal winter season with La Niña conditions, contrasting last year’s warmer, drier, El Niño event.
The National Oceanic and Atmospheric Administration has released official predictions favoring “a slowly developing La Niña” to influence temperature and precipitation across the United States until March.
La Niña, often called the anti-El Niño, brings below-average temperatures and above-average precipitation to the Midwest throughout the winter season. Trent Ford, Illinois State Climatologist, explained the phenomena.
“La Niña and its cousin El Niño are two phases of what we call the El Niño Southern Oscillation, and it’s a change in sea surface temperatures in the Tropical Pacific,” Ford said.
Sea surface temperatures affect the way jet streams move in the atmosphere, influencing weather patterns across the globe.
Get The Daily Illini in your inbox!
“La Niña is what we call ‘the cool tongue,’ where there is anomalously cool surface water, especially off the coast of South America,” Ford said.
There is a 60% chance of a La Niña event that is expected to persist until March 2025, according to the National Weather Service Climate Prediction Center. This means C-U can expect wetter overall conditions this winter.
However, this prediction doesn’t necessarily indicate higher levels of snowfall, which is dictated by the timing of precipitation systems and cold air.
“If we don’t get the timing of the cold air just right, it’s going to fall as everybody’s favorite weather — 35-degree rain,” Ford explained.
Ford also noted that during La Niña winters, Central Illinois is likely to have a “higher risk of cold air outbreaks, meaning potentially dangerous wind chills.” However, these risks are dependent on the strength of the La Niña event.
A strong La Niña occurs when Pacific temperatures drop to less than negative-1.5 to negative-two degrees Celsius below average. The last La Niña winter in Champaign was strong, but this year, a moderate La Niña phase is predicted, though Ford said this could change as we approach the winter season.
The intensity of La Niña is not the only factor determining how C-U residents feel its effects — climate change also plays a key role. Ford broke down its impact, explaining how Illinois residents might experience the phenomenon now.
“Climate change is acting on decadal to century time scales, so when we think about the trends in winter climate in Illinois, we’re getting warmer, which actually counteracts the effect of La Niña — but for precipitation, we’re getting wetter, which actually enhances the effect,” said Ford.
Ford continued by referencing the difficulty in predicting how Illinois residents will actually feel during the upcoming winter season, noting people don’t experience winter as an average.
“There could be mild weather in Champaign through December and January, but an intense cold snap in February,” Ford said. “People will perceive that winter as being really harsh because it’s the extreme weather that has the impacts, not necessarily the average.”
Ford also highlighted that weather in Illinois is dependent on more than just a La Niña event.
“We have lots of other factors that influence our winter weather, like Arctic Sea ice, snow extent in Eurasia, sea surface temperatures and pressure in the Atlantic and the Indian Ocean,” Ford said. “All of those things play huge roles, but we can’t predict them very accurately right now.”
Forecasting the likelihood of a La Niña event is fairly accurate, and Ford confirmed it is only a matter of time before it forms. However, predicting the extent of its impact on C-U is extremely complex.
“We’re still a good two-and-a-half months from the heart of climatological winter, and there are very few things that we can predict really well that affect our weather and climate that far out,” Ford said.
