S
M
T
W
T
F
S
30
81°
69°
31
91°
72°
1
94°
77°
2
96°
78°
3
92°
79°
4
93°
78°
5
87°
67°
6
78°
64°
7
79°
66°
8
88°
72°
9
88°
64°
10
79°
64°
11
81°
64°
12
81°
67°
13
85°
66°
14
77°
64°
15
80°
65°
16
78°
62°
17
77°
63°
18
76°
58°
19
77°
64°
20
78°
63°
21
74°
63°
22
71°
62°
23
73°
62°
24
78°
61°
25
79°
62°
26
78°
62°
27
77°
62°
28
79°
63°
29
78°
62°
30
78°
62°
1
76°
56°
2
71°
51°
3
64°
47°
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 64° to 88°, with overnight lows between 47° and 72°. The average high for September is 78° with an average low of 62°. 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.
