S
M
T
W
T
F
S
26
66°
50°
27
66°
48°
28
70°
59°
29
63°
50°
30
63°
46°
31
63°
43°
1
63°
50°
2
66°
48°
3
64°
52°
4
70°
57°
5
61°
55°
6
63°
54°
7
64°
55°
8
66°
54°
9
64°
52°
10
64°
48°
11
75°
48°
12
75°
54°
13
75°
57°
14
66°
57°
15
64°
52°
16
63°
54°
17
63°
48°
18
64°
55°
19
61°
54°
20
63°
46°
21
66°
43°
22
63°
43°
23
64°
45°
24
72°
41°
25
66°
50°
26
70°
57°
27
70°
59°
28
72°
57°
29
70°
50°
30
65°
53°
31
64°
53°
1
61°
52°
2
63°
57°
3
63°
52°
4
62°
49°
5
62°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Dumbarton
Dumbarton's August 2026 forecast shows daily high temperatures ranging from 61° to 65°, with overnight lows between 49° and 57°. The average high for August is 63° with an average low of 52°. 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 Dumbarton. See also: September | October | November.
