S
M
T
W
T
F
S
26
65°
46°
27
82°
44°
28
78°
55°
29
69°
50°
30
60°
40°
1
65°
37°
2
58°
35°
3
65°
29°
4
78°
45°
5
75°
53°
6
66°
49°
7
65°
40°
8
73°
35°
9
75°
52°
10
75°
50°
11
72°
46°
12
76°
41°
13
78°
48°
14
63°
41°
15
72°
38°
16
75°
50°
17
89°
59°
18
90°
56°
19
90°
62°
20
77°
59°
21
61°
51°
22
69°
54°
23
81°
60°
24
76°
61°
25
79°
58°
26
78°
62°
27
81°
61°
28
82°
60°
29
N/A
30
79°
50°
31
79°
55°
1
80°
54°
2
78°
52°
3
78°
54°
4
81°
59°
5
85°
63°
6
78°
62°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
May Weather in New Castle
New Castle's May 2026 forecast shows daily high temperatures ranging from 78° to 85°, with overnight lows between 50° and 63°. The average high for May 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 May weather will actually feel in New Castle. See also: June | July | August.
