S
M
T
W
T
F
S
30
80°
64°
31
87°
69°
1
92°
75°
2
95°
71°
3
89°
70°
4
89°
69°
5
85°
65°
6
83°
63°
7
79°
65°
8
79°
64°
9
84°
63°
10
78°
60°
11
77°
60°
12
76°
58°
13
72°
57°
14
73°
55°
15
75°
54°
16
79°
59°
17
78°
58°
18
71°
57°
19
74°
59°
20
76°
58°
21
75°
58°
22
74°
56°
23
72°
55°
24
73°
54°
25
76°
55°
26
75°
49°
27
65°
45°
28
63°
43°
29
63°
45°
30
64°
42°
1
63°
46°
2
65°
52°
3
66°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in DeKalb
DeKalb's September 2026 forecast shows daily high temperatures ranging from 63° to 95°, with overnight lows between 42° and 71°. The average high for September is 75° 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 DeKalb. See also: October | November | December.
