Will Illinois see a rainy, cool fall or a dry, warm autumn? What experts predict
After a period of “false fall” in the metro-east in early August, what temperatures can residents expect when the autumnal season actually begins?
Although southwest Illinois got a short break from extended extreme heat, temperatures are expected to climb as high as 97 degrees Fahrenheit in Belleville in the coming days, according to the National Weather Service St. Louis office.
Meteorological fall begins Monday, Sept. 1 and runs through the end of November, although astronomical fall won’t begin until the Monday, Sept. 22 autumn equinox.
The weather service’s Climate Prediction Center forecasts in its three-month seasonal outlook, released July 17, the metro-east region has a 33 to 40% chance of seeing above-normal temperatures from August to October.
The seasonal precipitation outlook for the three-month period reports southwestern Illinois has equal chances of seeing above- or below-normal precipitation.
Here’s what to know about fall weather, including a prediction from the Farmers’ Almanac and scientific data from meteorologists with the NWS.
What is typical fall weather for Belleville?
The NWS St. Louis office provides monthly climate data from 1991 to 2020. Here’s what to know about average fall weather in Belleville.
August:
- Average minimum temperature: 65.3 degrees
- Average maximum temperature: 89.1 degrees
- Average overall temperature: 77.2 degrees
- Total normal precipitation: 3.92 inches
September:
- Average minimum temperature: 56.9 degrees
- Average maximum temperature: 83.3 degrees
- Average overall temperature: 70.1 degrees
- Total normal precipitation: 3.35 inches
October:
- Average minimum temperature: 46.7 degrees
- Average maximum temperature: 72.6 degrees
- Average overall temperature: 59.7 degrees
- Total normal precipitation: 3.12 inches
November:
- Average minimum temperature: 36.9 degrees
- Average maximum temperature: 58.1 degrees
- Average overall temperature: 47.5 degrees
- Total normal precipitation: 3.6 inches
Farmers’ Almanac fall predictions for the Midwest
The almanac predicts a “flirty, flurry fall” across the U.S. this year.
The Farmers’ Almanac’s 2025 Autumn Outlook calls for a fair and chilly beginning of fall for Illinois and surrounding states, with the season progressing to more precipitation and potential snow at the end.
Midwest residents can expect “fair” weather for Halloween, the almanac says, with potential rain in Michigan and Ohio.
The organization makes predictions based on a mysterious formula that considers factors such as planetary positioning, sunspot activity and tidal action of the moon.
“The only person who knows the exact formula is the Farmers’ Almanac weather prognosticator who goes by the pseudonym of Caleb Weatherbee,” the organization’s website says. “To protect this proprietary formula, the editors of the Farmers’ Almanac prefer to keep both Caleb’s true identity and the formula a closely guarded brand secret.”
The Farmers’ Almanac has provided extended forecasts since 1818, according to its website.
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This story was originally published August 13, 2025 at 4:45 AM.
