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°
45°
10
55°
38°
11
53°
38°
12
59°
43°
13
56°
40°
14
55°
40°
15
57°
43°
16
56°
44°
17
59°
45°
18
59°
45°
19
61°
46°
20
61°
46°
21
60°
47°
22
58°
47°
23
58°
48°
24
57°
47°
25
58°
48°
26
58°
47°
27
59°
44°
28
59°
43°
29
60°
49°
30
59°
49°
31
59°
48°
1
60°
48°
2
59°
46°
3
62°
49°
4
65°
49°
5
60°
45°
6
59°
46°
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 53° to 66°, with overnight lows between 38° and 49°. The average high for May is 59° with an average low of 45°. 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.
