S
M
T
W
T
F
S
30
86°
59°
31
82°
58°
1
80°
61°
2
82°
64°
3
81°
59°
4
81°
57°
5
83°
60°
6
82°
63°
7
81°
57°
8
80°
58°
9
78°
62°
10
83°
56°
11
79°
55°
12
78°
55°
13
78°
60°
14
82°
60°
15
84°
61°
16
85°
60°
17
84°
60°
18
84°
59°
19
83°
52°
20
77°
52°
21
74°
56°
22
76°
57°
23
79°
57°
24
80°
58°
25
81°
53°
26
80°
49°
27
76°
50°
28
72°
49°
29
71°
49°
30
71°
49°
1
Hist. Avg.
73°
47°
2
Hist. Avg.
72°
47°
3
Hist. Avg.
72°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Foster
Foster's September 2026 forecast shows daily high temperatures ranging from 71° to 86°, with overnight lows between 49° and 64°. The average high for September is 80° with an average low of 57°. 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 Foster. See also: October | November | December.
