S
M
T
W
T
F
S
30
78°
55°
31
81°
59°
1
84°
52°
2
81°
53°
3
77°
52°
4
78°
53°
5
78°
60°
6
82°
58°
7
84°
57°
8
77°
58°
9
76°
58°
10
79°
57°
11
78°
55°
12
79°
56°
13
77°
55°
14
74°
49°
15
74°
49°
16
73°
48°
17
73°
50°
18
74°
54°
19
76°
54°
20
77°
55°
21
78°
51°
22
72°
47°
23
71°
52°
24
70°
53°
25
77°
47°
26
75°
45°
27
Hist. Avg.
70°
45°
28
Hist. Avg.
70°
45°
29
Hist. Avg.
70°
45°
30
Hist. Avg.
69°
44°
1
Hist. Avg.
69°
44°
2
Hist. Avg.
68°
44°
3
Hist. Avg.
68°
43°
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 70° to 84°, with overnight lows between 45° and 60°. The average high for September is 77° 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.
