S
M
T
W
T
F
S
30
90°
62°
31
73°
61°
1
89°
54°
2
88°
60°
3
89°
60°
4
89°
62°
5
86°
60°
6
91°
65°
7
88°
64°
8
90°
63°
9
95°
60°
10
95°
62°
11
88°
62°
12
89°
62°
13
86°
63°
14
87°
61°
15
86°
60°
16
84°
61°
17
84°
58°
18
86°
59°
19
83°
56°
20
85°
57°
21
84°
52°
22
79°
55°
23
80°
55°
24
80°
54°
25
80°
55°
26
83°
55°
27
77°
54°
28
75°
49°
29
75°
44°
30
72°
42°
1
72°
42°
2
73°
44°
3
74°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Sun Valley
Sun Valley's September 2026 forecast shows daily high temperatures ranging from 72° to 95°, with overnight lows between 42° and 63°. The average high for September is 82° with an average low of 55°. 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 Sun Valley. See also: October | November | December.
