S
M
T
W
T
F
S
26
60°
39°
27
69°
37°
28
66°
39°
29
64°
41°
30
54°
45°
1
61°
39°
2
57°
43°
3
54°
38°
4
70°
39°
5
77°
49°
6
64°
51°
7
60°
41°
8
57°
43°
9
61°
45°
10
69°
49°
11
58°
45°
12
62°
38°
13
65°
45°
14
63°
48°
15
64°
47°
16
76°
45°
17
86°
57°
18
86°
59°
19
N/A
20
85°
51°
21
62°
45°
22
64°
45°
23
57°
46°
24
56°
48°
25
64°
52°
26
72°
53°
27
73°
52°
28
72°
51°
29
69°
52°
30
73°
53°
31
74°
54°
1
75°
50°
2
65°
49°
3
64°
48°
4
64°
53°
5
68°
53°
6
70°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
May Weather in Cornwall
Cornwall's May 2026 forecast shows daily high temperatures ranging from 56° to 85°, with overnight lows between 45° and 54°. The average high for May is 68° 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 Cornwall. See also: June | July | August.
