S
M
T
W
T
F
S
30
66°
51°
31
65°
52°
1
66°
50°
2
66°
55°
3
68°
51°
4
67°
49°
5
67°
51°
6
66°
49°
7
64°
49°
8
68°
55°
9
68°
49°
10
66°
48°
11
66°
53°
12
69°
55°
13
67°
52°
14
65°
52°
15
66°
56°
16
68°
56°
17
69°
54°
18
69°
50°
19
67°
45°
20
60°
44°
21
56°
49°
22
58°
44°
23
59°
44°
24
58°
47°
25
58°
42°
26
57°
41°
27
54°
43°
28
55°
45°
29
53°
43°
30
53°
44°
1
58°
45°
2
Hist. Avg.
58°
46°
3
Hist. Avg.
58°
46°
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 53° to 69°, with overnight lows between 41° and 56°. The average high for September is 63° with an average low of 49°. 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.
