S
M
T
W
T
F
S
30
99°
80°
31
86°
68°
1
92°
70°
2
93°
75°
3
91°
77°
4
95°
76°
5
97°
74°
6
98°
79°
7
100°
78°
8
101°
80°
9
100°
79°
10
100°
79°
11
98°
77°
12
97°
77°
13
98°
76°
14
95°
74°
15
93°
73°
16
96°
75°
17
97°
74°
18
97°
75°
19
98°
74°
20
91°
72°
21
88°
65°
22
89°
65°
23
89°
66°
24
90°
65°
25
91°
68°
26
95°
71°
27
92°
65°
28
85°
62°
29
86°
62°
30
87°
61°
1
85°
61°
2
85°
62°
3
86°
61°
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 85° to 101°, with overnight lows between 61° and 80°. The average high for September is 93° with an average low of 70°. 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.
