S
M
T
W
T
F
S
26
77°
55°
27
75°
58°
28
75°
61°
29
76°
61°
30
82°
60°
31
82°
62°
1
81°
62°
2
82°
61°
3
81°
61°
4
80°
60°
5
79°
61°
6
80°
59°
7
78°
61°
8
79°
61°
9
78°
56°
10
80°
58°
11
81°
60°
12
Hist. Avg.
78°
57°
13
Hist. Avg.
78°
57°
14
Hist. Avg.
78°
57°
15
Hist. Avg.
77°
57°
16
Hist. Avg.
77°
57°
17
Hist. Avg.
77°
56°
18
Hist. Avg.
77°
56°
19
Hist. Avg.
77°
56°
20
Hist. Avg.
77°
56°
21
Hist. Avg.
77°
56°
22
Hist. Avg.
76°
56°
23
Hist. Avg.
76°
55°
24
Hist. Avg.
76°
55°
25
Hist. Avg.
76°
55°
26
Hist. Avg.
76°
55°
27
Hist. Avg.
76°
55°
28
Hist. Avg.
75°
54°
29
Hist. Avg.
75°
54°
30
Hist. Avg.
75°
54°
31
Hist. Avg.
74°
54°
1
Hist. Avg.
74°
54°
2
Hist. Avg.
74°
53°
3
Hist. Avg.
74°
53°
4
Hist. Avg.
73°
53°
5
Hist. Avg.
73°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
August Weather in Southwest Harbor
Southwest Harbor's August 2026 forecast shows daily high temperatures ranging from 75° to 82°, with overnight lows between 55° and 62°. The average high for August is 79° with an average low of 60°. 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.
