S
M
T
W
T
F
S
26
70°
46°
27
70°
46°
28
59°
45°
29
55°
43°
30
54°
36°
1
52°
36°
2
61°
32°
3
72°
52°
4
75°
46°
5
54°
37°
6
46°
34°
7
61°
32°
8
72°
41°
9
64°
45°
10
64°
37°
11
64°
37°
12
79°
48°
13
68°
48°
14
75°
43°
15
86°
55°
16
81°
59°
17
68°
57°
18
75°
61°
19
59°
42°
20
63°
45°
21
59°
47°
22
57°
47°
23
66°
53°
24
77°
58°
25
77°
56°
26
78°
58°
27
79°
60°
28
78°
60°
29
78°
59°
30
77°
60°
31
77°
61°
1
78°
54°
2
78°
58°
3
73°
55°
4
73°
55°
5
77°
60°
6
78°
61°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Decorah
Decorah's May 2026 forecast shows daily high temperatures ranging from 57° to 79°, with overnight lows between 42° and 61°. The average high for May is 73° with an average low of 55°. 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 Decorah. See also: June | July | August.
