S
M
T
W
T
F
S
30
82°
56°
31
79°
63°
1
78°
54°
2
81°
54°
3
82°
55°
4
88°
55°
5
84°
60°
6
89°
65°
7
86°
62°
8
86°
59°
9
67°
48°
10
68°
50°
11
76°
52°
12
72°
50°
13
72°
49°
14
75°
54°
15
73°
51°
16
75°
52°
17
69°
48°
18
75°
52°
19
74°
50°
20
69°
46°
21
68°
45°
22
72°
44°
23
73°
45°
24
73°
45°
25
72°
48°
26
73°
49°
27
69°
46°
28
70°
44°
29
65°
43°
30
66°
44°
1
65°
43°
2
61°
42°
3
62°
40°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Sion
Sion's September 2026 forecast shows daily high temperatures ranging from 61° to 89°, with overnight lows between 40° and 65°. The average high for September is 73° with an average low of 49°. 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 Sion. See also: October | November | December.
