S
M
T
W
T
F
S
30
72°
53°
31
78°
56°
1
79°
47°
2
77°
48°
3
71°
47°
4
72°
49°
5
72°
56°
6
76°
54°
7
77°
48°
8
70°
52°
9
69°
54°
10
71°
53°
11
72°
52°
12
73°
50°
13
70°
51°
14
67°
45°
15
68°
45°
16
67°
43°
17
67°
45°
18
66°
50°
19
71°
50°
20
69°
51°
21
71°
48°
22
66°
42°
23
65°
47°
24
64°
50°
25
69°
44°
26
61°
45°
27
68°
48°
28
69°
47°
29
Hist. Avg.
65°
44°
30
Hist. Avg.
65°
44°
1
Hist. Avg.
64°
44°
2
Hist. Avg.
64°
43°
3
Hist. Avg.
64°
43°
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 61° to 79°, with overnight lows between 42° and 56°. The average high for September is 70° with an average low of 49°. 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.
