S
M
T
W
T
F
S
30
88°
78°
31
87°
79°
1
89°
79°
2
88°
78°
3
88°
79°
4
87°
79°
5
88°
78°
6
88°
79°
7
89°
79°
8
89°
78°
9
88°
77°
10
87°
78°
11
88°
79°
12
87°
78°
13
88°
78°
14
88°
77°
15
87°
77°
16
88°
78°
17
88°
78°
18
87°
77°
19
88°
78°
20
87°
79°
21
88°
79°
22
88°
78°
23
87°
79°
24
86°
78°
25
87°
77°
26
88°
78°
27
87°
79°
28
87°
79°
29
88°
78°
30
89°
78°
1
89°
77°
2
87°
78°
3
87°
78°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Capital Hill
Capital Hill's September 2026 forecast shows daily high temperatures ranging from 86° to 89°, with overnight lows between 77° and 79°. The average high for September is 88° with an average low of 78°. 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 Capital Hill. See also: October | November | December.