S
M
T
W
T
F
S
30
81°
49°
31
81°
49°
1
79°
50°
2
78°
50°
3
78°
47°
4
79°
46°
5
77°
41°
6
76°
36°
7
68°
39°
8
68°
42°
9
73°
45°
10
76°
45°
11
77°
41°
12
76°
43°
13
76°
42°
14
75°
38°
15
73°
37°
16
69°
41°
17
74°
43°
18
76°
42°
19
77°
42°
20
76°
41°
21
74°
41°
22
66°
39°
23
62°
37°
24
69°
37°
25
70°
33°
26
69°
35°
27
65°
33°
28
63°
33°
29
63°
28°
30
61°
33°
1
60°
38°
2
65°
38°
3
70°
36°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mammoth Lakes
Mammoth Lakes's September 2026 forecast shows daily high temperatures ranging from 60° to 81°, with overnight lows between 28° and 50°. The average high for September is 72° with an average low of 40°. 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 Mammoth Lakes. See also: October | November | December.
