S
M
T
W
T
F
S
30
90°
59°
31
90°
58°
1
76°
53°
2
80°
57°
3
75°
58°
4
81°
54°
5
84°
54°
6
87°
58°
7
93°
60°
8
92°
63°
9
95°
67°
10
96°
66°
11
97°
64°
12
92°
63°
13
90°
62°
14
89°
60°
15
89°
62°
16
85°
61°
17
91°
62°
18
90°
60°
19
83°
58°
20
86°
63°
21
86°
60°
22
89°
60°
23
83°
59°
24
81°
56°
25
80°
57°
26
80°
56°
27
79°
55°
28
80°
56°
29
81°
55°
30
80°
59°
1
79°
55°
2
80°
57°
3
86°
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 75° to 97°, with overnight lows between 53° and 67°. The average high for September is 85° with an average low of 59°. 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.
