S
M
T
W
T
F
S
30
88°
68°
31
91°
67°
1
87°
67°
2
87°
69°
3
88°
67°
4
87°
68°
5
90°
69°
6
91°
66°
7
89°
65°
8
86°
66°
9
86°
66°
10
87°
65°
11
87°
65°
12
88°
67°
13
88°
68°
14
85°
68°
15
Hist. Avg.
86°
68°
16
Hist. Avg.
86°
68°
17
Hist. Avg.
86°
67°
18
Hist. Avg.
86°
67°
19
Hist. Avg.
85°
67°
20
Hist. Avg.
85°
66°
21
Hist. Avg.
85°
66°
22
Hist. Avg.
85°
66°
23
Hist. Avg.
84°
66°
24
Hist. Avg.
84°
65°
25
Hist. Avg.
84°
65°
26
Hist. Avg.
84°
64°
27
Hist. Avg.
83°
64°
28
Hist. Avg.
83°
64°
29
Hist. Avg.
83°
64°
30
Hist. Avg.
82°
63°
1
Hist. Avg.
82°
63°
2
Hist. Avg.
82°
62°
3
Hist. Avg.
82°
62°
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 85° to 91°, with overnight lows between 65° and 69°. The average high for September is 88° 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.
