S
M
T
W
T
F
S
30
73°
57°
31
70°
54°
1
71°
57°
2
69°
62°
3
73°
62°
4
69°
52°
5
69°
55°
6
74°
57°
7
69°
54°
8
68°
54°
9
68°
53°
10
66°
50°
11
65°
49°
12
66°
50°
13
67°
52°
14
65°
48°
15
66°
51°
16
63°
47°
17
63°
51°
18
66°
52°
19
66°
51°
20
61°
48°
21
64°
51°
22
65°
51°
23
66°
47°
24
62°
45°
25
64°
45°
26
63°
48°
27
64°
47°
28
64°
50°
29
63°
49°
30
64°
50°
1
64°
50°
2
63°
49°
3
64°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Cosby
Cosby's September 2026 forecast shows daily high temperatures ranging from 61° to 74°, with overnight lows between 45° and 62°. 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 Cosby. See also: October | November | December.