S
M
T
W
T
F
S
26
88°
72°
27
88°
72°
28
82°
66°
29
86°
64°
30
79°
68°
31
70°
61°
1
79°
61°
2
81°
55°
3
81°
63°
4
72°
57°
5
73°
54°
6
77°
50°
7
73°
55°
8
75°
50°
9
81°
63°
10
81°
63°
11
82°
68°
12
82°
66°
13
77°
66°
14
75°
64°
15
79°
68°
16
75°
59°
17
77°
54°
18
79°
59°
19
77°
59°
20
82°
60°
21
79°
57°
22
78°
51°
23
74°
56°
24
79°
61°
25
85°
58°
26
80°
57°
27
79°
58°
28
83°
59°
29
82°
60°
30
78°
59°
31
81°
60°
1
77°
56°
2
71°
55°
3
72°
52°
4
76°
59°
5
74°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Janesville
Janesville's August 2026 forecast shows daily high temperatures ranging from 71° to 85°, with overnight lows between 51° and 61°. The average high for August is 78° with an average low of 58°. 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 Janesville. See also: September | October | November.
