S
M
T
W
T
F
S
26
54°
37°
27
53°
37°
28
52°
38°
29
55°
37°
30
53°
39°
1
53°
40°
2
54°
39°
3
53°
37°
4
52°
35°
5
54°
34°
6
55°
35°
7
56°
38°
8
56°
43°
9
59°
44°
10
62°
44°
11
56°
41°
12
57°
39°
13
56°
39°
14
55°
40°
15
57°
39°
16
58°
43°
17
59°
42°
18
59°
44°
19
58°
44°
20
61°
43°
21
61°
48°
22
66°
47°
23
65°
48°
24
62°
50°
25
68°
50°
26
65°
49°
27
63°
50°
28
63°
50°
29
71°
48°
30
71°
45°
31
67°
47°
1
68°
46°
2
73°
52°
3
72°
54°
4
75°
55°
5
76°
54°
6
75°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Southwest Harbor
Southwest Harbor's May 2026 forecast shows daily high temperatures ranging from 52° to 76°, with overnight lows between 34° and 55°. The average high for May is 61° 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 Southwest Harbor. See also: June | July | August.
