S
M
T
W
T
F
S
26
64°
41°
27
66°
46°
28
55°
41°
29
61°
41°
30
68°
43°
1
77°
39°
2
68°
50°
3
59°
50°
4
54°
43°
5
57°
43°
6
52°
39°
7
57°
36°
8
64°
43°
9
66°
43°
10
54°
36°
11
50°
34°
12
59°
34°
13
52°
41°
14
54°
41°
15
54°
41°
16
57°
41°
17
59°
41°
18
61°
39°
19
63°
48°
20
64°
52°
21
72°
52°
22
82°
50°
23
77°
53°
24
81°
55°
25
90°
63°
26
77°
51°
27
68°
49°
28
72°
57°
29
74°
54°
30
68°
52°
31
64°
49°
1
65°
49°
2
64°
50°
3
65°
50°
4
66°
51°
5
60°
48°
6
61°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Grantham
Grantham's May 2026 forecast shows daily high temperatures ranging from 60° to 90°, with overnight lows between 45° and 63°. The average high for May is 70° with an average low of 52°. 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 Grantham. See also: June | July | August.
