S
M
T
W
T
F
S
30
68°
63°
31
76°
65°
1
88°
70°
2
85°
67°
3
83°
65°
4
74°
64°
5
78°
59°
6
76°
56°
7
76°
55°
8
77°
54°
9
75°
65°
10
76°
58°
11
74°
51°
12
78°
53°
13
78°
56°
14
67°
51°
15
73°
64°
16
77°
60°
17
73°
53°
18
74°
55°
19
73°
55°
20
68°
55°
21
67°
56°
22
68°
53°
23
69°
52°
24
70°
53°
25
70°
50°
26
71°
51°
27
71°
53°
28
71°
53°
29
69°
52°
30
66°
52°
1
66°
53°
2
69°
51°
3
66°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Delaware
Delaware's September 2026 forecast shows daily high temperatures ranging from 66° to 77°, with overnight lows between 50° and 64°. The average high for September is 70° with an average low of 54°. 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 Delaware. See also: October | November | December.
