S
M
T
W
T
F
S
30
87°
65°
31
88°
64°
1
82°
65°
2
81°
67°
3
82°
68°
4
86°
68°
5
86°
66°
6
85°
67°
7
86°
65°
8
84°
62°
9
84°
65°
10
80°
67°
11
85°
63°
12
85°
62°
13
80°
64°
14
80°
66°
15
83°
65°
16
83°
63°
17
82°
60°
18
79°
59°
19
78°
59°
20
78°
63°
21
79°
60°
22
81°
63°
23
82°
63°
24
81°
62°
25
82°
63°
26
81°
56°
27
82°
55°
28
77°
56°
29
79°
55°
30
80°
58°
1
79°
58°
2
Hist. Avg.
77°
57°
3
Hist. Avg.
77°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Northwest
Northwest's September 2026 forecast shows daily high temperatures ranging from 77° to 88°, with overnight lows between 55° and 68°. The average high for September is 82° with an average low of 62°. 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 Northwest. See also: October | November | December.
