S
M
T
W
T
F
S
30
70°
46°
31
67°
45°
1
67°
43°
2
66°
39°
3
67°
43°
4
71°
47°
5
65°
38°
6
64°
36°
7
64°
36°
8
63°
35°
9
63°
35°
10
64°
36°
11
64°
36°
12
69°
40°
13
70°
41°
14
71°
42°
15
70°
44°
16
70°
38°
17
68°
35°
18
65°
34°
19
65°
37°
20
67°
44°
21
67°
35°
22
59°
42°
23
62°
41°
24
57°
41°
25
56°
40°
26
56°
39°
27
54°
35°
28
54°
32°
29
55°
39°
30
54°
41°
1
55°
35°
2
55°
32°
3
53°
29°
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 53° to 71°, with overnight lows between 29° and 47°. The average high for September is 63° with an average low of 39°. 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.
