S
M
T
W
T
F
S
30
90°
77°
31
90°
82°
1
92°
82°
2
91°
83°
3
90°
83°
4
89°
83°
5
90°
81°
6
88°
80°
7
89°
81°
8
88°
81°
9
90°
80°
10
89°
81°
11
90°
80°
12
90°
81°
13
89°
80°
14
90°
77°
15
86°
80°
16
86°
79°
17
87°
80°
18
87°
80°
19
88°
79°
20
87°
80°
21
87°
79°
22
88°
79°
23
86°
77°
24
85°
76°
25
86°
79°
26
86°
78°
27
85°
79°
28
86°
79°
29
87°
78°
30
86°
79°
1
85°
79°
2
86°
78°
3
85°
78°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Cudjoe Key
Cudjoe Key's September 2026 forecast shows daily high temperatures ranging from 85° to 92°, with overnight lows between 76° and 83°. The average high for September is 88° with an average low of 80°. 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 Cudjoe Key. See also: October | November | December.