S
M
T
W
T
F
S
26
68°
45°
27
61°
43°
28
54°
36°
29
54°
34°
30
52°
37°
1
52°
34°
2
66°
30°
3
72°
46°
4
63°
36°
5
50°
30°
6
48°
27°
7
61°
32°
8
73°
36°
9
61°
39°
10
63°
32°
11
70°
30°
12
73°
54°
13
72°
41°
14
79°
45°
15
90°
52°
16
81°
46°
17
77°
55°
18
64°
55°
19
54°
41°
20
57°
34°
21
63°
46°
22
61°
46°
23
70°
50°
24
81°
59°
25
84°
63°
26
86°
61°
27
84°
64°
28
84°
61°
29
82°
61°
30
81°
56°
31
75°
57°
1
79°
56°
2
80°
56°
3
78°
56°
4
79°
58°
5
80°
59°
6
75°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Janesville
Janesville's May 2026 forecast shows daily high temperatures ranging from 75° to 86°, with overnight lows between 55° and 64°. The average high for May is 81° with an average low of 59°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in Janesville. See also: June | July | August.
