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What is Illinois City, IL, Weather Like in October?

During the month of October, Illinois City, IL, has an average daytime high temperature of 65°F and an average overnight low temperature dropping to 44°F. Around 2.78 inches of precipitation is received during the month, with about 32.63 inches falling in a typical year. Snow is not common in Illinois City, IL.

October 2025: Actual vs. Average Temperatures

Showing temperatures through today (October 21, 2025)
Actual High Average High Actual Low Average Low

Month Summary
Average High: 76 F (+9.1 vs avg)
Average Low: 55 F (+9.4 vs avg)

This month was significantly warmer than average.

Actual data from: MID_ILNI2

Illinois City, IL Daily Weather Averages for October

Recorded at Illinois City Dam 16 (usc00114355), 6.6 miles WNW of Illinois City, IL
Day Avg Temps (°F) Precip (in) Snow (in) Degree Days (°F)
Low High Mean Month Year Month Year Heat Cool
10/1 49 F 71 F 60 F 0.10" 29.95" N/A N/A 6 F 1.3 F
10/2 49 F 71 F 60 F 0.19" 30.04" N/A N/A 6.3 F 1.2 F
10/3 49 F 70 F 60 F 0.29" 30.14" N/A N/A 6.7 F 1.2 F
10/4 48 F 70 F 59 F 0.39" 30.24" N/A N/A 7 F 1.1 F
10/5 48 F 70 F 59 F 0.48" 30.33" N/A N/A 7.4 F 1 F
10/6 47 F 69 F 58 F 0.57" 30.42" N/A N/A 7.7 F 1 F
10/7 47 F 69 F 58 F 0.66" 30.51" N/A N/A 8.1 F 0.9 F
10/8 47 F 68 F 57 F 0.74" 30.59" N/A N/A 8.5 F 0.9 F
10/9 46 F 68 F 57 F 0.84" 30.69" N/A N/A 8.9 F 0.8 F
10/10 46 F 67 F 56 F 0.93" 30.78" N/A N/A 9.3 F 0.7 F
10/11 45 F 67 F 56 F 1.02" 30.87" N/A N/A 9.7 F 0.7 F
10/12 45 F 66 F 56 F 1.11" 30.96" N/A N/A 10.1 F 0.6 F
10/13 45 F 66 F 55 F 1.20" 31.05" N/A N/A 10.4 F 0.5 F
10/14 44 F 65 F 55 F 1.29" 31.14" N/A N/A 10.8 F 0.4 F
10/15 44 F 65 F 54 F 1.38" 31.23" N/A N/A 11.2 F 0.3 F
10/16 43 F 64 F 54 F 1.47" 31.32" N/A N/A 11.6 F 0.3 F
10/17 43 F 64 F 53 F 1.57" 31.42" N/A N/A 12.1 F 0.2 F
10/18 42 F 63 F 53 F 1.66" 31.51" N/A N/A 12.5 F 0.2 F
10/19 42 F 63 F 52 F 1.75" 31.60" N/A N/A 13 F 0.2 F
10/20 42 F 62 F 52 F 1.84" 31.69" N/A N/A 13.5 F 0.2 F
10/21 41 F 61 F 51 F 1.93" 31.78" N/A N/A 14 F 0.2 F
10/22 41 F 61 F 51 F 2.02" 31.87" N/A N/A 14.4 F 0.2 F
10/23 40 F 60 F 50 F 2.10" 31.95" N/A N/A 14.9 F 0.2 F
10/24 40 F 60 F 50 F 2.19" 32.04" N/A N/A 15.4 F 0.2 F
10/25 39 F 59 F 49 F 2.27" 32.12" N/A N/A 15.8 F 0.1 F
10/26 39 F 59 F 49 F 2.36" 32.21" N/A N/A 16.3 F 0.1 F
10/27 39 F 58 F 48 F 2.44" 32.29" N/A N/A 16.7 F 0.1 F
10/28 38 F 58 F 48 F 2.53" 32.38" N/A N/A 17.2 F 0.1 F
10/29 38 F 57 F 47 F 2.61" 32.46" N/A N/A 17.7 F 0.1 F
10/30 37 F 57 F 47 F 2.70" 32.55" N/A N/A 18.1 F 0.1 F
10/31 37 F 56 F 46 F 2.78" 32.63" N/A N/A 18.6 F 0.1 F