S
M
T
W
T
F
S
30
96°
73°
31
95°
70°
1
95°
70°
2
94°
68°
3
95°
70°
4
95°
73°
5
96°
72°
6
95°
71°
7
93°
71°
8
92°
70°
9
94°
71°
10
94°
70°
11
93°
67°
12
87°
67°
13
91°
66°
14
91°
68°
15
90°
68°
16
86°
67°
17
89°
67°
18
90°
58°
19
88°
60°
20
82°
60°
21
83°
64°
22
84°
65°
23
89°
66°
24
88°
65°
25
90°
66°
26
89°
65°
27
89°
65°
28
90°
58°
29
88°
61°
30
80°
62°
1
Hist. Avg.
81°
56°
2
Hist. Avg.
81°
56°
3
Hist. Avg.
80°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Decatur
Decatur's September 2026 forecast shows daily high temperatures ranging from 80° to 96°, with overnight lows between 58° and 73°. The average high for September is 90° with an average low of 67°. 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 Decatur. See also: October | November | December.
