S
M
T
W
T
F
S
30
90°
77°
31
90°
82°
1
90°
80°
2
90°
83°
3
90°
83°
4
91°
83°
5
90°
82°
6
90°
81°
7
90°
84°
8
91°
84°
9
93°
82°
10
92°
81°
11
91°
83°
12
91°
83°
13
93°
83°
14
93°
81°
15
91°
82°
16
92°
81°
17
86°
82°
18
86°
82°
19
86°
81°
20
87°
82°
21
86°
82°
22
86°
81°
23
87°
82°
24
86°
82°
25
86°
80°
26
87°
82°
27
86°
82°
28
86°
80°
29
84°
79°
30
86°
80°
1
85°
81°
2
85°
80°
3
84°
79°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Big Coppitt Key
Big Coppitt Key's September 2026 forecast shows daily high temperatures ranging from 84° to 93°, with overnight lows between 79° and 84°. The average high for September is 88° with an average low of 82°. 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 Big Coppitt Key. See also: October | November | December.
