S
M
T
W
T
F
S
29
39°
21°
30
50°
34°
31
43°
35°
1
50°
33°
2
38°
29°
3
41°
32°
4
47°
35°
5
44°
35°
6
45°
31°
7
40°
28°
8
42°
26°
9
45°
26°
10
50°
38°
11
51°
33°
12
50°
39°
13
50°
47°
14
60°
46°
15
51°
43°
16
61°
45°
17
63°
42°
18
56°
44°
19
54°
40°
20
50°
35°
21
51°
36°
22
56°
40°
23
57°
41°
24
53°
35°
25
50°
34°
26
51°
33°
27
53°
38°
28
52°
38°
29
53°
37°
30
55°
37°
1
54°
34°
2
53°
33°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
April Weather in Southwest Harbor
Southwest Harbor's April 2026 forecast shows daily high temperatures ranging from 50° to 63°, with overnight lows between 33° and 47°. The average high for April is 54° with an average low of 39°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how April weather will actually feel in Southwest Harbor. See also: May | June | July.
