S
M
T
W
T
F
S
30
66°
52°
31
71°
47°
1
70°
46°
2
65°
46°
3
63°
47°
4
63°
45°
5
64°
44°
6
63°
48°
7
64°
48°
8
68°
47°
9
66°
48°
10
62°
50°
11
63°
49°
12
66°
48°
13
65°
48°
14
64°
45°
15
67°
44°
16
61°
43°
17
59°
42°
18
59°
46°
19
62°
48°
20
65°
48°
21
65°
47°
22
64°
43°
23
63°
46°
24
62°
46°
25
61°
45°
26
63°
45°
27
62°
44°
28
59°
40°
29
60°
41°
30
57°
40°
1
55°
39°
2
53°
38°
3
59°
41°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Portland
Portland's September 2026 forecast shows daily high temperatures ranging from 53° to 71°, with overnight lows between 38° and 52°. The average high for September is 63° with an average low of 45°. 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 Portland. See also: October | November | December.
