S
M
T
W
T
F
S
26
82°
64°
27
82°
63°
28
81°
62°
29
81°
62°
30
75°
61°
31
74°
59°
1
74°
56°
2
73°
56°
3
74°
58°
4
74°
59°
5
75°
59°
6
75°
60°
7
73°
61°
8
74°
61°
9
75°
60°
10
78°
57°
11
76°
54°
12
79°
60°
13
75°
61°
14
80°
60°
15
82°
59°
16
75°
60°
17
74°
60°
18
80°
61°
19
79°
59°
20
79°
53°
21
74°
53°
22
76°
54°
23
77°
52°
24
77°
58°
25
79°
58°
26
79°
56°
27
80°
56°
28
78°
51°
29
77°
52°
30
77°
57°
31
79°
57°
1
78°
49°
2
76°
50°
3
70°
55°
4
74°
56°
5
74°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Southwest Harbor
Southwest Harbor's August 2026 forecast shows daily high temperatures ranging from 70° to 82°, with overnight lows between 49° and 64°. The average high for August is 77° with an average low of 58°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Southwest Harbor. See also: September | October | November.
