S
M
T
W
T
F
S
26
70°
49°
27
72°
47°
28
57°
42°
29
57°
42°
30
56°
37°
1
55°
35°
2
62°
45°
3
72°
44°
4
77°
42°
5
58°
36°
6
54°
36°
7
59°
39°
8
62°
43°
9
68°
45°
10
66°
47°
11
70°
46°
12
74°
52°
13
76°
53°
14
73°
48°
15
70°
49°
16
73°
55°
17
74°
54°
18
74°
54°
19
75°
50°
20
72°
52°
21
69°
46°
22
66°
45°
23
67°
46°
24
68°
47°
25
67°
47°
26
67°
48°
27
68°
48°
28
69°
49°
29
70°
56°
30
74°
58°
31
71°
53°
1
73°
54°
2
76°
57°
3
77°
60°
4
80°
60°
5
80°
62°
6
78°
62°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Marshalltown
Marshalltown's May 2026 forecast shows daily high temperatures ranging from 54° to 80°, with overnight lows between 36° and 62°. The average high for May is 70° with an average low of 50°. 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 Marshalltown. See also: June | July | August.
