S
M
T
W
T
F
S
30
95°
70°
31
92°
69°
1
93°
70°
2
92°
68°
3
91°
67°
4
90°
66°
5
90°
66°
6
91°
67°
7
91°
67°
8
92°
70°
9
90°
71°
10
92°
70°
11
92°
70°
12
91°
71°
13
92°
70°
14
91°
70°
15
93°
69°
16
93°
69°
17
91°
70°
18
92°
68°
19
91°
67°
20
90°
66°
21
91°
67°
22
93°
62°
23
Hist. Avg.
88°
65°
24
Hist. Avg.
88°
65°
25
Hist. Avg.
88°
64°
26
Hist. Avg.
87°
64°
27
Hist. Avg.
87°
64°
28
Hist. Avg.
87°
64°
29
Hist. Avg.
86°
63°
30
Hist. Avg.
86°
63°
1
Hist. Avg.
86°
63°
2
Hist. Avg.
86°
62°
3
Hist. Avg.
85°
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 90° to 95°, with overnight lows between 62° and 71°. The average high for September is 92° with an average low of 68°. 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.
