September was 1.5 degrees cooler than average and 0.88 inches wetter than average for Illinois. Year to date temperatures were 3.3 degrees below average and the 6th coolest January-September on record. The year to date precipitation was 32.91 inches, 2.5 inches above average.
The statewide average temperature for September in Illinois was 64.4 degrees, 1.5 degrees below the 1981-2010 average.
The statewide average precipitation for September in Illinois was 4.12 inches, 0.88 inches above average. The heaviest rains fell across western and central Illinois with amounts of 6 to 9 inches (map below). A second area of heavy rains occurred south of Interstate 70 near Effingham. The largest monthly total reported so far is Beardstown with 10.72 inches.