S
M
T
W
T
F
S
30
85°
54°
31
84°
51°
1
83°
52°
2
84°
53°
3
87°
54°
4
87°
56°
5
88°
56°
6
88°
55°
7
87°
57°
8
88°
56°
9
87°
55°
10
81°
55°
11
79°
56°
12
85°
57°
13
86°
56°
14
87°
56°
15
86°
55°
16
84°
54°
17
82°
55°
18
84°
55°
19
86°
54°
20
83°
54°
21
Hist. Avg.
80°
54°
22
Hist. Avg.
80°
53°
23
Hist. Avg.
79°
53°
24
Hist. Avg.
79°
53°
25
Hist. Avg.
79°
53°
26
Hist. Avg.
78°
52°
27
Hist. Avg.
78°
52°
28
Hist. Avg.
78°
52°
29
Hist. Avg.
77°
52°
30
Hist. Avg.
77°
51°
1
Hist. Avg.
77°
51°
2
Hist. Avg.
76°
51°
3
Hist. Avg.
76°
51°
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 79° to 88°, with overnight lows between 51° and 57°. The average high for September is 85° with an average low of 55°. 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.
