S
M
T
W
T
F
S
30
91°
82°
31
99°
82°
1
90°
82°
2
98°
83°
3
96°
82°
4
96°
81°
5
95°
79°
6
94°
80°
7
95°
81°
8
92°
77°
9
91°
78°
10
93°
77°
11
94°
79°
12
91°
78°
13
93°
79°
14
92°
77°
15
90°
76°
16
89°
73°
17
90°
75°
18
88°
76°
19
90°
76°
20
90°
75°
21
91°
76°
22
91°
76°
23
89°
75°
24
86°
75°
25
87°
74°
26
88°
75°
27
84°
72°
28
84°
68°
29
83°
67°
30
83°
67°
1
84°
69°
2
86°
71°
3
87°
68°
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 83° to 96°, with overnight lows between 67° and 82°. The average high for September is 90° with an average low of 75°. 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.
