S
M
T
W
T
F
S
30
83°
54°
31
77°
54°
1
77°
53°
2
76°
54°
3
77°
59°
4
75°
53°
5
80°
53°
6
76°
52°
7
75°
51°
8
74°
52°
9
76°
53°
10
78°
58°
11
78°
57°
12
73°
55°
13
73°
56°
14
72°
49°
15
71°
48°
16
Hist. Avg.
68°
50°
17
Hist. Avg.
68°
49°
18
Hist. Avg.
68°
49°
19
Hist. Avg.
67°
49°
20
Hist. Avg.
67°
48°
21
Hist. Avg.
67°
48°
22
Hist. Avg.
66°
48°
23
Hist. Avg.
66°
47°
24
Hist. Avg.
66°
47°
25
Hist. Avg.
65°
46°
26
Hist. Avg.
65°
46°
27
Hist. Avg.
64°
46°
28
Hist. Avg.
64°
45°
29
Hist. Avg.
64°
45°
30
Hist. Avg.
63°
45°
1
Hist. Avg.
63°
44°
2
Hist. Avg.
62°
44°
3
Hist. Avg.
62°
44°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Sun Valley
Sun Valley's September 2026 forecast shows daily high temperatures ranging from 71° to 83°, with overnight lows between 48° and 59°. The average high for September is 76° with an average low of 54°. 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.
