S
M
T
W
T
F
S
26
89°
70°
27
89°
70°
28
88°
69°
29
87°
68°
30
83°
67°
31
81°
67°
1
80°
66°
2
81°
66°
3
83°
67°
4
82°
62°
5
81°
62°
6
80°
61°
7
82°
65°
8
80°
67°
9
80°
67°
10
81°
66°
11
83°
66°
12
83°
67°
13
85°
67°
14
86°
66°
15
85°
67°
16
80°
67°
17
80°
66°
18
82°
66°
19
84°
65°
20
85°
65°
21
78°
56°
22
77°
57°
23
78°
58°
24
77°
59°
25
79°
64°
26
83°
65°
27
87°
66°
28
87°
67°
29
89°
60°
30
87°
57°
31
79°
58°
1
79°
61°
2
80°
64°
3
86°
66°
4
87°
65°
5
88°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Illiana
Illiana's August 2026 forecast shows daily high temperatures ranging from 77° to 89°, with overnight lows between 56° and 70°. The average high for August is 83° with an average low of 64°. 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 Illiana. See also: September | October | November.
