S
M
T
W
T
F
S
30
90°
62°
31
93°
64°
1
94°
64°
2
94°
63°
3
90°
64°
4
88°
64°
5
92°
63°
6
94°
64°
7
94°
63°
8
93°
64°
9
93°
60°
10
89°
56°
11
87°
56°
12
87°
55°
13
86°
60°
14
85°
59°
15
89°
58°
16
90°
60°
17
89°
64°
18
92°
65°
19
83°
64°
20
84°
63°
21
90°
63°
22
91°
62°
23
88°
63°
24
88°
63°
25
90°
62°
26
89°
62°
27
89°
61°
28
83°
62°
29
83°
62°
30
84°
63°
1
88°
61°
2
90°
62°
3
89°
61°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mountain House
Mountain House's September 2026 forecast shows daily high temperatures ranging from 83° to 94°, with overnight lows between 55° and 65°. The average high for September is 89° with an average low of 62°. 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 House. See also: October | November | December.
