S
M
T
W
T
F
S
30
84°
67°
31
89°
71°
1
92°
74°
2
94°
73°
3
94°
74°
4
90°
71°
5
82°
68°
6
77°
61°
7
78°
59°
8
84°
68°
9
85°
67°
10
77°
53°
11
79°
57°
12
82°
61°
13
80°
64°
14
83°
65°
15
79°
59°
16
76°
54°
17
78°
57°
18
78°
57°
19
75°
55°
20
72°
52°
21
76°
57°
22
69°
56°
23
71°
56°
24
77°
55°
25
79°
57°
26
78°
56°
27
77°
56°
28
78°
57°
29
78°
57°
30
78°
56°
1
77°
53°
2
76°
47°
3
63°
43°
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 63° to 85°, with overnight lows between 43° and 68°. The average high for September is 77° with an average low of 57°. 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.
