S
M
T
W
T
F
S
30
77°
34°
31
75°
37°
1
72°
45°
2
57°
37°
3
52°
41°
4
50°
40°
5
53°
40°
6
51°
40°
7
58°
38°
8
59°
42°
9
62°
41°
10
58°
40°
11
59°
39°
12
57°
39°
13
58°
38°
14
57°
40°
15
61°
37°
16
65°
42°
17
64°
41°
18
59°
39°
19
59°
39°
20
63°
40°
21
63°
40°
22
62°
39°
23
62°
40°
24
60°
39°
25
60°
40°
26
62°
39°
27
62°
40°
28
61°
40°
29
61°
39°
30
60°
38°
1
61°
39°
2
61°
39°
3
59°
38°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Sierra
Sierra's September 2026 forecast shows daily high temperatures ranging from 50° to 65°, with overnight lows between 37° and 42°. The average high for September is 59° with an average low of 39°. 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 Sierra. See also: October | November | December.
