S
M
T
W
T
F
S
30
79°
54°
31
79°
57°
1
81°
52°
2
78°
53°
3
77°
59°
4
83°
61°
5
83°
60°
6
82°
56°
7
77°
52°
8
76°
52°
9
79°
58°
10
76°
58°
11
79°
59°
12
77°
57°
13
80°
51°
14
74°
48°
15
73°
48°
16
73°
49°
17
74°
52°
18
77°
55°
19
80°
55°
20
81°
56°
21
74°
52°
22
79°
54°
23
76°
51°
24
80°
46°
25
71°
44°
26
70°
44°
27
Hist. Avg.
72°
45°
28
Hist. Avg.
72°
45°
29
Hist. Avg.
71°
44°
30
Hist. Avg.
71°
44°
1
Hist. Avg.
70°
44°
2
Hist. Avg.
70°
43°
3
Hist. Avg.
70°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in New Castle
New Castle's September 2026 forecast shows daily high temperatures ranging from 70° to 83°, with overnight lows between 44° and 61°. The average high for September is 77° 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 New Castle. See also: October | November | December.
