S
M
T
W
T
F
S
30
76°
47°
31
85°
53°
1
73°
55°
2
62°
51°
3
62°
49°
4
70°
50°
5
71°
49°
6
76°
49°
7
72°
48°
8
75°
50°
9
78°
53°
10
78°
52°
11
78°
51°
12
77°
52°
13
76°
49°
14
77°
47°
15
72°
49°
16
70°
49°
17
70°
43°
18
71°
44°
19
70°
48°
20
69°
47°
21
69°
42°
22
68°
42°
23
68°
44°
24
67°
43°
25
66°
45°
26
68°
42°
27
69°
49°
28
65°
48°
29
67°
47°
30
66°
48°
1
65°
46°
2
64°
40°
3
65°
40°
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 62° to 78°, with overnight lows between 40° and 55°. The average high for September is 70° with an average low of 47°. 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.
