S
M
T
W
T
F
S
26
86°
71°
27
83°
68°
28
85°
71°
29
87°
68°
30
82°
69°
31
83°
70°
1
82°
68°
2
83°
71°
3
86°
72°
4
87°
71°
5
88°
68°
6
82°
65°
7
84°
71°
8
88°
70°
9
83°
71°
10
88°
71°
11
84°
68°
12
86°
70°
13
87°
71°
14
87°
68°
15
82°
64°
16
80°
64°
17
80°
69°
18
81°
70°
19
82°
70°
20
84°
69°
21
84°
70°
22
85°
69°
23
84°
68°
24
89°
68°
25
88°
69°
26
88°
68°
27
81°
67°
28
83°
68°
29
80°
62°
30
81°
61°
31
79°
61°
1
78°
67°
2
78°
68°
3
85°
67°
4
86°
68°
5
85°
65°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in New Castle
New Castle's August 2026 forecast shows daily high temperatures ranging from 78° to 89°, with overnight lows between 61° and 72°. The average high for August is 84° with an average low of 68°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in New Castle. See also: September | October | November.