S
M
T
W
T
F
S
30
90°
68°
31
95°
69°
1
99°
73°
2
99°
73°
3
98°
72°
4
99°
72°
5
94°
69°
6
85°
67°
7
83°
67°
8
83°
66°
9
82°
67°
10
83°
64°
11
81°
59°
12
78°
59°
13
80°
60°
14
78°
58°
15
80°
62°
16
80°
63°
17
81°
62°
18
82°
62°
19
81°
63°
20
81°
63°
21
80°
62°
22
81°
62°
23
81°
61°
24
80°
61°
25
81°
60°
26
81°
59°
27
80°
60°
28
80°
60°
29
79°
59°
30
79°
59°
1
78°
58°
2
78°
58°
3
77°
57°
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 77° to 99°, with overnight lows between 57° and 73°. The average high for September is 83° 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 Decatur. See also: October | November | December.
