S
M
T
W
T
F
S
30
75°
45°
31
87°
56°
1
68°
55°
2
65°
55°
3
63°
54°
4
64°
52°
5
71°
51°
6
70°
54°
7
72°
50°
8
80°
53°
9
89°
56°
10
80°
51°
11
71°
45°
12
64°
53°
13
63°
52°
14
70°
51°
15
66°
52°
16
80°
54°
17
84°
53°
18
73°
52°
19
75°
49°
20
79°
51°
21
73°
50°
22
70°
49°
23
76°
51°
24
74°
49°
25
74°
50°
26
75°
51°
27
68°
44°
28
67°
44°
29
66°
42°
30
66°
42°
1
67°
41°
2
65°
41°
3
64°
40°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Forest Grove
Forest Grove's September 2026 forecast shows daily high temperatures ranging from 64° to 84°, with overnight lows between 40° and 54°. The average high for September is 72° with an average low of 48°. 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 Forest Grove. See also: October | November | December.
