S
M
T
W
T
F
S
30
72°
50°
31
69°
50°
1
68°
51°
2
67°
50°
3
67°
48°
4
68°
48°
5
72°
56°
6
75°
57°
7
72°
54°
8
76°
45°
9
70°
57°
10
75°
54°
11
77°
46°
12
70°
50°
13
75°
56°
14
75°
45°
15
74°
41°
16
63°
41°
17
63°
43°
18
64°
48°
19
68°
50°
20
67°
50°
21
66°
52°
22
69°
51°
23
70°
51°
24
69°
50°
25
65°
50°
26
72°
52°
27
70°
40°
28
72°
36°
29
60°
37°
30
58°
40°
1
57°
36°
2
56°
39°
3
58°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Napierville
Napierville's September 2026 forecast shows daily high temperatures ranging from 56° to 77°, with overnight lows between 36° and 57°. The average high for September is 68° with an average low of 48°. 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 Napierville. See also: October | November | December.
