S
M
T
W
T
F
S
30
90°
69°
31
89°
70°
1
89°
67°
2
88°
67°
3
87°
69°
4
87°
64°
5
86°
69°
6
88°
67°
7
87°
68°
8
86°
67°
9
87°
68°
10
87°
68°
11
86°
67°
12
84°
67°
13
82°
66°
14
82°
66°
15
81°
65°
16
84°
66°
17
81°
65°
18
81°
62°
19
82°
64°
20
81°
59°
21
79°
59°
22
80°
60°
23
81°
62°
24
82°
63°
25
83°
64°
26
82°
63°
27
83°
63°
28
78°
60°
29
79°
57°
30
82°
60°
1
78°
56°
2
76°
56°
3
Hist. Avg.
79°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Rockford
Rockford's September 2026 forecast shows daily high temperatures ranging from 76° to 90°, with overnight lows between 56° and 70°. The average high for September is 83° with an average low of 64°. 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 Rockford. See also: October | November | December.
