S
M
T
W
T
F
S
26
53°
37°
27
62°
40°
28
56°
35°
29
60°
33°
30
55°
36°
1
64°
33°
2
73°
40°
3
82°
43°
4
79°
43°
5
59°
43°
6
66°
37°
7
77°
47°
8
84°
49°
9
80°
50°
10
81°
52°
11
75°
49°
12
74°
49°
13
76°
50°
14
69°
47°
15
66°
50°
16
66°
52°
17
71°
53°
18
71°
53°
19
73°
54°
20
78°
55°
21
79°
50°
22
68°
46°
23
70°
47°
24
68°
47°
25
66°
46°
26
67°
47°
27
68°
46°
28
71°
47°
29
73°
57°
30
82°
58°
31
78°
59°
1
82°
59°
2
79°
58°
3
82°
59°
4
76°
59°
5
75°
58°
6
74°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Grinnell
Grinnell's May 2026 forecast shows daily high temperatures ranging from 59° to 84°, with overnight lows between 33° and 59°. The average high for May is 74° 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 Grinnell. See also: June | July | August.
