S
M
T
W
T
F
S
30
93°
61°
31
97°
64°
1
97°
68°
2
95°
70°
3
95°
70°
4
99°
72°
5
100°
72°
6
100°
72°
7
95°
70°
8
99°
73°
9
99°
77°
10
92°
69°
11
90°
68°
12
94°
70°
13
97°
71°
14
94°
73°
15
88°
66°
16
87°
64°
17
87°
62°
18
82°
60°
19
78°
59°
20
80°
59°
21
82°
58°
22
87°
63°
23
86°
64°
24
86°
64°
25
87°
63°
26
86°
64°
27
86°
63°
28
85°
63°
29
85°
62°
30
83°
61°
1
81°
54°
2
72°
51°
3
72°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mountain View
Mountain View's September 2026 forecast shows daily high temperatures ranging from 72° to 99°, with overnight lows between 49° and 77°. The average high for September is 86° with an average low of 63°. 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 Mountain View. See also: October | November | December.
