S
M
T
W
T
F
S
30
81°
70°
31
90°
72°
1
93°
70°
2
93°
72°
3
93°
73°
4
93°
73°
5
86°
72°
6
81°
59°
7
79°
62°
8
85°
68°
9
81°
55°
10
78°
55°
11
81°
58°
12
78°
56°
13
72°
56°
14
75°
54°
15
71°
51°
16
75°
53°
17
74°
52°
18
75°
50°
19
74°
48°
20
77°
54°
21
74°
53°
22
74°
52°
23
76°
52°
24
76°
53°
25
75°
54°
26
76°
53°
27
76°
53°
28
75°
52°
29
75°
53°
30
73°
52°
1
72°
45°
2
62°
41°
3
60°
38°
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 60° to 85°, with overnight lows between 38° and 68°. The average high for September is 75° with an average low of 53°. 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.
