S
M
T
W
T
F
S
30
92°
69°
31
88°
68°
1
91°
68°
2
95°
68°
3
94°
75°
4
96°
67°
5
92°
69°
6
85°
68°
7
91°
67°
8
82°
59°
9
83°
50°
10
83°
62°
11
89°
56°
12
76°
56°
13
70°
56°
14
67°
48°
15
71°
50°
16
72°
52°
17
70°
49°
18
68°
49°
19
73°
48°
20
75°
51°
21
74°
48°
22
80°
56°
23
77°
56°
24
78°
55°
25
70°
55°
26
71°
54°
27
77°
54°
28
75°
53°
29
71°
51°
30
70°
43°
1
61°
42°
2
62°
38°
3
61°
38°
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 61° to 89°, with overnight lows between 38° and 62°. The average high for September is 73° with an average low of 51°. 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.
