Fall crops are being harvested, but recent weather felt more like summer.
State Climatologist Trent Ford said many Illinois residents got a taste of fall temperatures in early September, but the month ended much warmer.
“September average temperatures ranged from the mid-60s in northern Illinois to the low-70s in southern Illinois,” he said. “Most of the state was between 1 and 5 degrees above normal, with the highest departures in the northern third of the state.”
Ford said there were a lot of regional variations in temperature in September with daytime highs reaching 96 degrees in Mount Vernon and 95 in Peoria, while nighttime lows dipped down to 39 in Normal and 36 in Elgin. It was the second-warmest September on record in Chicago.
But it all evened out in the end with the statewide average September temperature pegged at 68.5 degrees, 1.8 degrees above the 1991-2020 average.
Ford said rainfall also varied by region in September.
“Total September precipitation ranged from less than 1 inch in far northwest Illinois to over 8 inches in parts of southern Illinois,” he said. “Most areas of the state south of Interstate 64 were 1 to 5 inches wetter than normal for the month, while much of central and northern Illinois were 1 to 3 inches drier than normal.”
Ford said rain from remnants of Hurricane Helene in the southern portion of the state caused the drastic differences, noting that it was the second-driest September on record in Mount Carroll to the north while Carbondale in the south was the fourth wettest with more than 8 inches for the month.
Statewide total September precipitation was pegged at 2.73 inches, 0.62 inches below the 1991–2020 average.
Drought remains a concern
Considering those totals, Ford said drought is still a concern in the central and northern portions of the state.
“Much of the region had a top-five-driest start to September on record, including the driest first 20 days of the month in Quincy, Danville, Moline, and Rockford,” he said.
As of Oct. 3, the U.S. Drought Monitor indicated 70% of the state is experiencing abnormally dry to moderate drought conditions.
Meanwhile, the hurricane eliminated drought concerns for most of southern Illinois and dropped rain across the Ohio River Basin that improved water levels on the Mississippi River.
Statewide topsoil moisture supply was rated 44% short to very short, 49% adequate and just 7% surplus as of Sept. 30, the National Agricultural Statistics Service reported.
Harvest activity shifts into high gear
The overall warmer and drier September conditions continued to push the state’s harvest pace ahead of average.
USDA reported as of Sept. 30, 21% of corn and 24% of soybeans were harvested in Illinois compared to the five-year average of 16% and 11%, respectively. Winter wheat planting is also ahead of normal at 11% complete with 2% emerged.
Looking ahead, the Climate Prediction Center shows higher odds of a warmer and drier than normal October, but Ford said there will still be a more noticeable transition to fall conditions.
Meanwhile, the National Oceanic and Atmospheric Administration is predicting higher chances of a wetter than normal winter season.