S
M
T
W
T
F
S
30
82°
59°
31
79°
69°
1
88°
68°
2
73°
68°
3
85°
68°
4
84°
70°
5
79°
65°
6
77°
61°
7
77°
58°
8
81°
54°
9
84°
62°
10
85°
69°
11
79°
58°
12
75°
68°
13
80°
63°
14
76°
52°
15
75°
59°
16
80°
63°
17
83°
61°
18
80°
58°
19
72°
53°
20
72°
52°
21
69°
50°
22
72°
52°
23
74°
54°
24
75°
52°
25
68°
48°
26
67°
51°
27
75°
56°
28
76°
55°
29
71°
50°
30
73°
55°
1
72°
54°
2
70°
50°
3
71°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Downingtown
Downingtown's September 2026 forecast shows daily high temperatures ranging from 67° to 83°, with overnight lows between 48° and 68°. The average high for September is 74° with an average low of 55°. 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 Downingtown. See also: October | November | December.
