S
M
T
W
T
F
S
30
79°
62°
31
83°
63°
1
84°
57°
2
78°
56°
3
78°
56°
4
79°
55°
5
78°
55°
6
79°
61°
7
81°
56°
8
80°
59°
9
82°
60°
10
82°
60°
11
81°
59°
12
82°
60°
13
82°
60°
14
81°
59°
15
82°
60°
16
82°
59°
17
79°
58°
18
80°
59°
19
79°
58°
20
78°
58°
21
79°
56°
22
78°
50°
23
74°
55°
24
72°
56°
25
72°
56°
26
Hist. Avg.
74°
51°
27
Hist. Avg.
74°
50°
28
Hist. Avg.
74°
50°
29
Hist. Avg.
74°
50°
30
Hist. Avg.
73°
49°
1
Hist. Avg.
73°
49°
2
Hist. Avg.
73°
48°
3
Hist. Avg.
72°
48°
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 84°, with overnight lows between 50° and 63°. The average high for September is 79° 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.
