S
M
T
W
T
F
S
30
84°
67°
31
87°
66°
1
83°
68°
2
84°
68°
3
83°
69°
4
86°
70°
5
87°
66°
6
86°
67°
7
83°
65°
8
82°
66°
9
83°
65°
10
82°
66°
11
85°
66°
12
85°
65°
13
Hist. Avg.
83°
66°
14
Hist. Avg.
82°
66°
15
Hist. Avg.
82°
66°
16
Hist. Avg.
82°
66°
17
Hist. Avg.
82°
65°
18
Hist. Avg.
81°
65°
19
Hist. Avg.
81°
65°
20
Hist. Avg.
81°
64°
21
Hist. Avg.
81°
64°
22
Hist. Avg.
80°
64°
23
Hist. Avg.
80°
64°
24
Hist. Avg.
80°
63°
25
Hist. Avg.
80°
63°
26
Hist. Avg.
79°
62°
27
Hist. Avg.
79°
62°
28
Hist. Avg.
79°
62°
29
Hist. Avg.
79°
61°
30
Hist. Avg.
78°
61°
1
Hist. Avg.
78°
61°
2
Hist. Avg.
78°
60°
3
Hist. Avg.
78°
60°
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 82° to 87°, with overnight lows between 65° and 70°. The average high for September is 84° with an average low of 67°. 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.
