S
M
T
W
T
F
S
30
75°
54°
31
79°
58°
1
75°
56°
2
73°
54°
3
75°
53°
4
73°
54°
5
78°
64°
6
83°
62°
7
Hist. Avg.
76°
49°
8
Hist. Avg.
76°
48°
9
Hist. Avg.
76°
48°
10
Hist. Avg.
75°
48°
11
Hist. Avg.
75°
48°
12
Hist. Avg.
75°
48°
13
Hist. Avg.
75°
48°
14
Hist. Avg.
74°
47°
15
Hist. Avg.
74°
47°
16
Hist. Avg.
74°
47°
17
Hist. Avg.
74°
47°
18
Hist. Avg.
73°
46°
19
Hist. Avg.
73°
46°
20
Hist. Avg.
73°
46°
21
Hist. Avg.
72°
46°
22
Hist. Avg.
72°
46°
23
Hist. Avg.
72°
45°
24
Hist. Avg.
71°
45°
25
Hist. Avg.
71°
45°
26
Hist. Avg.
71°
45°
27
Hist. Avg.
70°
44°
28
Hist. Avg.
70°
44°
29
Hist. Avg.
69°
44°
30
Hist. Avg.
69°
44°
1
Hist. Avg.
69°
44°
2
Hist. Avg.
68°
43°
3
Hist. Avg.
68°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Downtown Portland
Downtown Portland's September 2026 forecast shows daily high temperatures ranging from 73° to 83°, with overnight lows between 53° and 64°. The average high for September is 76° with an average low of 57°. 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 Downtown Portland. See also: October | November | December.
