Monthly Historical AveragesDecatur, IL
Average Temperature
High
30°
Feels 32
Low
19°
Feels 19
Average Precipitation
11 Days
97.3mm
0cm
Content continues below
Daily Historical Averages
S
M
T
W
T
F
S
ForecastFriday, July 17, 2026
Day
30°Feels 38
Wind
13 km/h W
Gust
20 km/h
Humidity
77%
P.O.P
90%
Rain
~5 mm
Night
23°Feels 23
Wind
12 km/h S
Gust
18 km/h
Humidity
95%
P.O.P
40%
Rain
~1 mm
Historical AveragesJul 17
High
Feels
Low
Feels
Precip Frequency
Total Daylight
Humidity