S
M
T
W
T
F
S
26
67°
31°
27
73°
35°
28
65°
32°
29
53°
36°
30
48°
43°
1
57°
35°
2
48°
42°
3
47°
37°
4
54°
46°
5
55°
49°
6
57°
48°
7
54°
40°
8
53°
38°
9
55°
39°
10
56°
41°
11
56°
36°
12
58°
40°
13
57°
41°
14
58°
42°
15
58°
43°
16
59°
42°
17
57°
40°
18
58°
46°
19
57°
47°
20
61°
47°
21
62°
48°
22
65°
45°
23
59°
46°
24
58°
47°
25
61°
45°
26
62°
44°
27
61°
44°
28
60°
47°
29
60°
48°
30
62°
49°
31
62°
48°
1
63°
44°
2
61°
44°
3
62°
45°
4
61°
46°
5
62°
45°
6
63°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Castine
Castine's May 2026 forecast shows daily high temperatures ranging from 47° to 65°, with overnight lows between 35° and 49°. The average high for May is 58° with an average low of 44°. 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 Castine. See also: June | July | August.
