S
M
T
W
T
F
S
30
92°
72°
31
92°
71°
1
91°
71°
2
91°
70°
3
90°
71°
4
92°
71°
5
92°
70°
6
91°
70°
7
90°
65°
8
85°
68°
9
87°
69°
10
89°
64°
11
88°
65°
12
87°
66°
13
88°
67°
14
89°
68°
15
90°
67°
16
87°
66°
17
85°
62°
18
82°
62°
19
81°
67°
20
82°
61°
21
81°
60°
22
80°
60°
23
80°
65°
24
81°
65°
25
83°
64°
26
85°
65°
27
82°
64°
28
84°
65°
29
84°
64°
30
80°
63°
1
79°
62°
2
83°
56°
3
77°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mountain Brook
Mountain Brook's September 2026 forecast shows daily high temperatures ranging from 77° to 92°, with overnight lows between 56° and 72°. The average high for September is 86° with an average low of 66°. 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 Mountain Brook. See also: October | November | December.
