S
M
T
W
T
F
S
30
79°
55°
31
79°
64°
1
86°
66°
2
70°
64°
3
88°
66°
4
84°
68°
5
81°
63°
6
74°
59°
7
80°
60°
8
84°
65°
9
86°
72°
10
87°
63°
11
81°
55°
12
80°
61°
13
84°
62°
14
80°
58°
15
84°
63°
16
83°
61°
17
81°
59°
18
78°
56°
19
80°
57°
20
80°
57°
21
77°
59°
22
70°
58°
23
71°
58°
24
71°
57°
25
73°
54°
26
76°
54°
27
72°
50°
28
71°
54°
29
76°
56°
30
77°
56°
1
76°
55°
2
75°
56°
3
75°
53°
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 70° to 87°, with overnight lows between 50° and 72°. The average high for September is 78° with an average low of 58°. 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.
