S
M
T
W
T
F
S
30
98°
73°
31
98°
73°
1
98°
75°
2
100°
76°
3
92°
76°
4
92°
79°
5
97°
74°
6
93°
76°
7
98°
75°
8
98°
75°
9
96°
75°
10
91°
74°
11
98°
74°
12
99°
77°
13
98°
74°
14
97°
74°
15
99°
75°
16
98°
74°
17
93°
76°
18
95°
73°
19
96°
68°
20
97°
70°
21
98°
74°
22
99°
71°
23
98°
73°
24
96°
74°
25
94°
70°
26
90°
65°
27
95°
67°
28
96°
71°
29
95°
69°
30
92°
74°
1
92°
73°
2
84°
73°
3
85°
74°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Washington
Washington's September 2026 forecast shows daily high temperatures ranging from ° to °, with overnight lows between ° and °. The average high for September is ° with an average low of °. 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.
