S
M
T
W
T
F
S
30
81°
59°
31
85°
61°
1
86°
58°
2
82°
59°
3
81°
63°
4
86°
64°
5
87°
64°
6
86°
63°
7
83°
58°
8
80°
57°
9
82°
63°
10
83°
62°
11
82°
63°
12
83°
63°
13
84°
59°
14
77°
54°
15
76°
54°
16
77°
54°
17
77°
55°
18
80°
59°
19
82°
60°
20
83°
61°
21
75°
57°
22
79°
58°
23
77°
59°
24
81°
53°
25
74°
50°
26
73°
56°
27
72°
50°
28
Hist. Avg.
74°
51°
29
Hist. Avg.
73°
50°
30
Hist. Avg.
73°
50°
1
Hist. Avg.
72°
49°
2
Hist. Avg.
72°
49°
3
Hist. Avg.
72°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Washington
Washington's September 2026 forecast shows daily high temperatures ranging from 72° to 87°, with overnight lows between 50° and 64°. The average high for September is 80° with an average low of 58°. 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 Washington. See also: October | November | December.
