S
M
T
W
T
F
S
30
77°
48°
31
75°
44°
1
69°
43°
2
68°
45°
3
68°
43°
4
69°
44°
5
67°
43°
6
67°
42°
7
68°
43°
8
71°
46°
9
69°
48°
10
65°
43°
11
66°
45°
12
69°
44°
13
70°
48°
14
71°
46°
15
64°
42°
16
64°
42°
17
62°
41°
18
64°
45°
19
63°
40°
20
69°
48°
21
64°
47°
22
Hist. Avg.
66°
44°
23
Hist. Avg.
66°
44°
24
Hist. Avg.
65°
43°
25
Hist. Avg.
65°
43°
26
Hist. Avg.
64°
43°
27
Hist. Avg.
64°
42°
28
Hist. Avg.
63°
42°
29
Hist. Avg.
63°
42°
30
Hist. Avg.
62°
41°
1
Hist. Avg.
62°
41°
2
Hist. Avg.
61°
40°
3
Hist. Avg.
61°
40°
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 62° to 77°, with overnight lows between 40° and 48°. The average high for September is 68° with an average low of 44°. 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.
