S
M
T
W
T
F
S
30
71°
62°
31
73°
59°
1
75°
63°
2
78°
64°
3
80°
58°
4
79°
54°
5
76°
55°
6
74°
56°
7
75°
56°
8
71°
55°
9
74°
60°
10
72°
55°
11
69°
55°
12
69°
54°
13
70°
52°
14
68°
52°
15
71°
50°
16
72°
55°
17
70°
50°
18
65°
49°
19
70°
52°
20
72°
54°
21
72°
54°
22
71°
53°
23
70°
52°
24
65°
51°
25
69°
52°
26
68°
51°
27
69°
50°
28
59°
49°
29
58°
49°
30
60°
45°
1
56°
44°
2
57°
46°
3
62°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Belleville
Belleville's September 2026 forecast shows daily high temperatures ranging from 56° to 80°, with overnight lows between 44° and 64°. The average high for September is 69° with an average low of 52°. 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 Belleville. See also: October | November | December.