S
M
T
W
T
F
S
30
89°
76°
31
90°
77°
1
89°
77°
2
90°
76°
3
91°
76°
4
91°
75°
5
90°
76°
6
90°
76°
7
91°
75°
8
90°
76°
9
91°
76°
10
91°
75°
11
90°
75°
12
91°
74°
13
90°
75°
14
91°
76°
15
89°
75°
16
89°
75°
17
91°
76°
18
90°
75°
19
91°
75°
20
91°
74°
21
90°
74°
22
91°
76°
23
91°
76°
24
90°
75°
25
90°
76°
26
89°
76°
27
90°
75°
28
90°
75°
29
89°
74°
30
88°
74°
1
89°
75°
2
90°
74°
3
89°
71°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Dismal Key
Dismal Key's September 2026 forecast shows daily high temperatures ranging from 88° to 91°, with overnight lows between 71° and 77°. The average high for September is 90° with an average low of 75°. 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 Dismal Key. See also: October | November | December.
