S
M
T
W
T
F
S
30
81°
62°
31
81°
53°
1
80°
53°
2
74°
52°
3
75°
57°
4
77°
61°
5
82°
52°
6
81°
51°
7
73°
51°
8
74°
58°
9
76°
58°
10
76°
56°
11
73°
56°
12
71°
54°
13
72°
49°
14
71°
47°
15
70°
49°
16
71°
53°
17
70°
55°
18
77°
56°
19
79°
55°
20
76°
54°
21
77°
51°
22
73°
52°
23
69°
46°
24
68°
45°
25
67°
45°
26
67°
44°
27
Hist. Avg.
71°
49°
28
Hist. Avg.
71°
48°
29
Hist. Avg.
70°
48°
30
Hist. Avg.
70°
48°
1
Hist. Avg.
69°
47°
2
Hist. Avg.
69°
47°
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 Belvidere
Belvidere's September 2026 forecast shows daily high temperatures ranging from 67° to 82°, with overnight lows between 44° and 62°. The average high for September is 74° with an average low of 53°. 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 Belvidere. See also: October | November | December.
