S
M
T
W
T
F
S
30
78°
61°
31
81°
65°
1
83°
61°
2
84°
60°
3
77°
59°
4
78°
60°
5
79°
66°
6
83°
66°
7
84°
65°
8
78°
65°
9
77°
64°
10
82°
64°
11
82°
62°
12
81°
65°
13
79°
60°
14
78°
57°
15
74°
58°
16
73°
57°
17
73°
56°
18
74°
57°
19
78°
61°
20
79°
62°
21
78°
59°
22
74°
54°
23
72°
59°
24
73°
61°
25
77°
53°
26
76°
52°
27
Hist. Avg.
71°
55°
28
Hist. Avg.
71°
55°
29
Hist. Avg.
70°
54°
30
Hist. Avg.
70°
54°
1
Hist. Avg.
70°
53°
2
Hist. Avg.
69°
53°
3
Hist. Avg.
69°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Potomac
Potomac's September 2026 forecast shows daily high temperatures ranging from 72° to 84°, with overnight lows between 52° and 66°. The average high for September is 78° with an average low of 60°. 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 Potomac. See also: October | November | December.
