S
M
T
W
T
F
S
30
84°
42°
31
82°
44°
1
67°
47°
2
54°
48°
3
55°
40°
4
65°
40°
5
68°
43°
6
68°
44°
7
70°
45°
8
77°
46°
9
80°
48°
10
82°
49°
11
76°
48°
12
75°
47°
13
77°
45°
14
79°
46°
15
89°
48°
16
75°
44°
17
73°
43°
18
71°
40°
19
71°
41°
20
73°
46°
21
77°
47°
22
78°
48°
23
72°
45°
24
69°
39°
25
69°
41°
26
75°
44°
27
77°
46°
28
78°
47°
29
77°
47°
30
76°
46°
1
77°
47°
2
77°
47°
3
75°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mount Shasta
Mount Shasta's September 2026 forecast shows daily high temperatures ranging from 54° to 89°, with overnight lows between 39° and 49°. The average high for September is 74° with an average low of 45°. 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 Mount Shasta. See also: October | November | December.
