S
M
T
W
T
F
S
30
80°
56°
31
84°
61°
1
84°
57°
2
85°
56°
3
79°
55°
4
80°
56°
5
83°
60°
6
84°
61°
7
84°
60°
8
82°
59°
9
82°
60°
10
83°
59°
11
83°
59°
12
82°
60°
13
83°
58°
14
79°
54°
15
76°
55°
16
75°
56°
17
78°
54°
18
76°
53°
19
81°
56°
20
79°
57°
21
80°
55°
22
77°
54°
23
78°
54°
24
79°
55°
25
78°
49°
26
74°
54°
27
78°
54°
28
78°
54°
29
Hist. Avg.
76°
54°
30
Hist. Avg.
75°
54°
1
Hist. Avg.
75°
54°
2
Hist. Avg.
75°
53°
3
Hist. Avg.
74°
53°
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 74° to 85°, with overnight lows between 49° and 61°. The average high for September is 80° with an average low of 56°. 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.
