S
M
T
W
T
F
S
30
81°
56°
31
81°
59°
1
78°
58°
2
81°
54°
3
80°
48°
4
73°
49°
5
72°
56°
6
75°
56°
7
79°
50°
8
72°
51°
9
71°
53°
10
72°
56°
11
74°
55°
12
79°
56°
13
78°
55°
14
79°
54°
15
78°
51°
16
72°
53°
17
70°
45°
18
71°
45°
19
68°
43°
20
66°
42°
21
65°
43°
22
66°
50°
23
67°
43°
24
69°
44°
25
70°
50°
26
70°
50°
27
72°
51°
28
73°
48°
29
72°
44°
30
69°
45°
1
66°
46°
2
71°
47°
3
64°
39°
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 64° to 81°, with overnight lows between 39° and 59°. The average high for September is 73° with an average low of 50°. 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.
