S
M
T
W
T
F
S
30
97°
70°
31
96°
69°
1
96°
65°
2
95°
63°
3
93°
67°
4
95°
70°
5
95°
70°
6
96°
68°
7
94°
69°
8
93°
70°
9
95°
70°
10
95°
67°
11
94°
61°
12
89°
65°
13
92°
63°
14
92°
65°
15
91°
65°
16
86°
64°
17
90°
57°
18
90°
55°
19
83°
55°
20
80°
56°
21
81°
61°
22
83°
63°
23
88°
62°
24
87°
63°
25
89°
60°
26
88°
59°
27
81°
54°
28
86°
52°
29
80°
53°
30
78°
56°
1
Hist. Avg.
82°
56°
2
Hist. Avg.
82°
56°
3
Hist. Avg.
81°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Chattanooga
Chattanooga's September 2026 forecast shows daily high temperatures ranging from 78° to 97°, with overnight lows between 52° and 70°. The average high for September is 90° with an average low of 63°. 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 Chattanooga. See also: October | November | December.