S
M
T
W
T
F
S
30
89°
62°
31
86°
60°
1
81°
63°
2
82°
65°
3
86°
60°
4
86°
66°
5
88°
66°
6
88°
59°
7
87°
59°
8
80°
58°
9
80°
58°
10
83°
62°
11
85°
60°
12
85°
59°
13
78°
57°
14
77°
63°
15
82°
62°
16
85°
56°
17
84°
55°
18
76°
53°
19
75°
54°
20
75°
60°
21
76°
60°
22
77°
54°
23
75°
57°
24
74°
56°
25
75°
58°
26
78°
59°
27
80°
57°
28
80°
51°
29
73°
57°
30
74°
57°
1
73°
58°
2
78°
55°
3
77°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Potomac
Potomac's September 2026 forecast shows daily high temperatures ranging from 73° to 89°, with overnight lows between 49° and 66°. The average high for September is 80° with an average low of 58°. 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.
