S
M
T
W
T
F
S
30
84°
65°
31
87°
64°
1
87°
64°
2
86°
63°
3
82°
63°
4
83°
61°
5
79°
62°
6
79°
56°
7
80°
62°
8
85°
56°
9
81°
61°
10
78°
63°
11
84°
61°
12
82°
60°
13
83°
60°
14
84°
59°
15
84°
60°
16
85°
61°
17
Hist. Avg.
79°
55°
18
Hist. Avg.
79°
55°
19
Hist. Avg.
78°
54°
20
Hist. Avg.
78°
54°
21
Hist. Avg.
78°
54°
22
Hist. Avg.
77°
53°
23
Hist. Avg.
77°
53°
24
Hist. Avg.
77°
53°
25
Hist. Avg.
76°
53°
26
Hist. Avg.
76°
52°
27
Hist. Avg.
76°
52°
28
Hist. Avg.
75°
52°
29
Hist. Avg.
75°
51°
30
Hist. Avg.
75°
51°
1
Hist. Avg.
74°
51°
2
Hist. Avg.
74°
50°
3
Hist. Avg.
74°
50°
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 78° to 87°, with overnight lows between 56° and 65°. The average high for September is 83° with an average low of 61°. 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.
