S
M
T
W
T
F
S
30
71°
46°
31
79°
36°
1
72°
54°
2
74°
47°
3
72°
45°
4
76°
45°
5
79°
39°
6
80°
43°
7
63°
41°
8
69°
33°
9
73°
35°
10
76°
42°
11
75°
56°
12
77°
39°
13
75°
46°
14
61°
35°
15
72°
29°
16
79°
39°
17
68°
48°
18
64°
46°
19
60°
45°
20
58°
39°
21
69°
35°
22
66°
41°
23
66°
35°
24
75°
41°
25
74°
45°
26
68°
42°
27
70°
41°
28
62°
36°
29
63°
33°
30
67°
38°
1
60°
34°
2
58°
32°
3
60°
34°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Alta
Alta's September 2026 forecast shows daily high temperatures ranging from 58° to 75°, with overnight lows between 32° and 45°. The average high for September is 66° with an average low of 37°. 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 Alta. See also: October | November | December.
