S
M
T
W
T
F
S
26
71°
33°
27
75°
35°
28
71°
37°
29
69°
38°
30
53°
45°
1
62°
36°
2
55°
40°
3
54°
33°
4
72°
36°
5
84°
49°
6
63°
47°
7
60°
35°
8
59°
31°
9
51°
30°
10
68°
43°
11
62°
36°
12
62°
32°
13
49°
38°
14
56°
48°
15
65°
52°
16
74°
56°
17
80°
46°
18
79°
54°
19
87°
62°
20
82°
45°
21
62°
35°
22
64°
39°
23
67°
45°
24
63°
44°
25
66°
48°
26
71°
47°
27
69°
50°
28
71°
50°
29
69°
45°
30
65°
49°
31
67°
48°
1
69°
49°
2
66°
48°
3
66°
47°
4
65°
50°
5
68°
51°
6
72°
51°
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 62° to 87°, with overnight lows between 35° and 62°. The average high for May is 70° with an average low of 48°. 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.
