S
M
T
W
T
F
S
30
79°
54°
31
75°
52°
1
73°
48°
2
70°
57°
3
62°
59°
4
71°
59°
5
66°
54°
6
67°
48°
7
73°
53°
8
72°
50°
9
68°
52°
10
71°
54°
11
68°
50°
12
70°
52°
13
67°
53°
14
66°
52°
15
64°
49°
16
67°
54°
17
69°
53°
18
64°
50°
19
70°
52°
20
68°
52°
21
65°
51°
22
64°
51°
23
65°
50°
24
67°
50°
25
63°
49°
26
65°
51°
27
68°
51°
28
66°
49°
29
64°
48°
30
60°
48°
1
61°
45°
2
59°
44°
3
57°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mount Desert
Mount Desert's September 2026 forecast shows daily high temperatures ranging from 57° to 73°, with overnight lows between 44° and 59°. The average high for September is 66° with an average low of 51°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Mount Desert. See also: October | November | December.
