S
M
T
W
T
F
S
30
50°
41°
31
43°
37°
1
50°
27°
2
47°
29°
3
54°
28°
4
58°
48°
5
57°
47°
6
62°
40°
7
63°
49°
8
54°
47°
9
53°
43°
10
48°
40°
11
59°
35°
12
52°
32°
13
51°
30°
14
59°
29°
15
52°
44°
16
51°
41°
17
52°
38°
18
54°
39°
19
50°
37°
20
47°
34°
21
44°
37°
22
38°
32°
23
37°
29°
24
50°
20°
25
54°
36°
26
54°
36°
27
55°
33°
28
46°
30°
29
38°
31°
30
34°
27°
1
30°
17°
2
35°
17°
3
35°
21°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Summit
Summit's September 2026 forecast shows daily high temperatures ranging from 30° to 35°, with overnight lows between 17° and 21°. The average high for September is 33° with an average low of 18°. 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 Summit. See also: October | November | December.
