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Illiopolis, IL

78°F
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Illiopolis

Illinois

78°
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Illiopolis, IL Weather
Today WinterCast Local {stormName} Tracker Hourly 10-Day Radar MinuteCast® Monthly Air Quality Health & Activities

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Today Hourly 10-Day Radar MinuteCast®

Monthly

Air Quality Health & Activities
Extreme Heat Warning

August

January February March April May June July August September October November December

2026

2025 2026 2027

10-Day

S
M
T
W
T
F
S
26
Mostly sunny and humid
89°
69°
27
Humid; a shower in the a.m.
89°
70°
28
Sunny and uncomfortably humid
90°
70°
29
Sunlit, hot and very humid
91°
68°
30
Thickening clouds and humid
89°
69°
31
A t-storm around in the a.m.
89°
68°
1
Mostly sunny and less humid
86°
66°
2
Sunshine and a few clouds
82°
62°
3
A shower and thunderstorm
82°
66°
4
A shower in the afternoon
81°
67°
5
Scintillating sunshine
82°
67°
6
Sunny and humid
84°
66°
7
Plenty of sunshine
86°
67°
8
Increasing clouds
86°
67°
9
Some sun, then clouds; humid
85°
68°
10
Humid with clouds and sun
87°
67°
11
Mostly sunny and less humid
85°
67°
12
Mostly sunny
87°
66°
13
Mostly cloudy and humid
87°
66°
14
Sunshine, hot and very humid
91°
66°
15
Humid with a stray t-storm
90°
64°
16
Partly sunny and humid
87°
66°
17
Humid with some sun
86°
64°
18
A shower and t-storm; humid
84°
65°
19
A t-shower in spots; humid
87°
58°
20
Sunshine and less humid
81°
57°
21
Partly sunny
79°
56°
22
Plenty of sun
79°
57°
23
Mostly sunny
80°
57°
24
Sunny to partly cloudy
81°
58°
25
Mostly sunny
81°
61°
26
Clouds and sunshine
80°
57°
27
Humid with sunshine
87°
63°
28
Mostly sunny and humid
87°
63°
29
Mostly sunny and humid
86°
60°
30
Humid with partial sunshine
87°
58°
31
Mainly cloudy and not as warm
79°
57°
1
Mainly cloudy
78°
59°
2
A couple of morning showers
79°
55°
3
Morning rain, then a shower
77°
55°
4
Partly sunny
78°
60°
5
Mostly cloudy
78°
60°

Temperature Graph

°F
100° 90° 80° 70° 60° Aug
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo

August Weather in Illiopolis

Illiopolis's August 2026 forecast shows daily high temperatures ranging from 77° to 91°, with overnight lows between 55° and 70°. The average high for August is 84° with an average low of 63°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Illiopolis. See also: September | October | November.

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World North America United States Illinois Illiopolis

Weather Near Illiopolis:

  • Champaign, IL
  • Decatur, IL
  • Springfield, IL
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