S
M
T
W
T
F
S
30
81°
63°
31
81°
55°
1
80°
53°
2
76°
54°
3
75°
59°
4
77°
63°
5
82°
54°
6
81°
52°
7
74°
52°
8
74°
59°
9
76°
59°
10
77°
57°
11
73°
58°
12
71°
56°
13
72°
50°
14
71°
49°
15
71°
51°
16
72°
55°
17
71°
57°
18
78°
57°
19
79°
55°
20
78°
56°
21
77°
53°
22
73°
52°
23
70°
47°
24
69°
45°
25
67°
46°
26
68°
46°
27
67°
45°
28
Hist. Avg.
70°
48°
29
Hist. Avg.
70°
48°
30
Hist. Avg.
70°
47°
1
Hist. Avg.
69°
47°
2
Hist. Avg.
69°
46°
3
Hist. Avg.
68°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in DeKalb
DeKalb's September 2026 forecast shows daily high temperatures ranging from 67° to 82°, with overnight lows between 45° and 63°. The average high for September is 75° with an average low of 54°. 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.
