S
M
T
W
T
F
S
30
69°
51°
31
69°
50°
1
70°
53°
2
71°
57°
3
70°
60°
4
73°
60°
5
76°
59°
6
79°
51°
7
76°
50°
8
69°
50°
9
69°
51°
10
68°
53°
11
68°
56°
12
67°
51°
13
68°
54°
14
72°
54°
15
73°
55°
16
69°
56°
17
68°
55°
18
72°
54°
19
72°
48°
20
70°
51°
21
70°
47°
22
71°
44°
23
64°
45°
24
62°
46°
25
63°
47°
26
62°
43°
27
62°
42°
28
61°
46°
29
60°
42°
30
60°
41°
1
61°
43°
2
66°
41°
3
63°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in South Harpswell
South Harpswell's September 2026 forecast shows daily high temperatures ranging from 60° to 79°, with overnight lows between 41° and 60°. The average high for September is 68° with an average low of 50°. 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 South Harpswell. See also: October | November | December.
