S
M
T
W
T
F
S
26
63°
43°
27
75°
38°
28
74°
52°
29
57°
45°
30
52°
35°
1
45°
33°
2
43°
35°
3
60°
27°
4
73°
47°
5
72°
53°
6
56°
45°
7
59°
33°
8
60°
38°
9
69°
48°
10
62°
40°
11
61°
33°
12
67°
32°
13
68°
45°
14
54°
43°
15
66°
38°
16
70°
46°
17
85°
54°
18
89°
59°
19
87°
66°
20
68°
49°
21
67°
48°
22
65°
49°
23
63°
51°
24
67°
53°
25
77°
55°
26
82°
61°
27
78°
53°
28
74°
46°
29
76°
49°
30
71°
43°
31
70°
49°
1
71°
49°
2
72°
49°
3
71°
54°
4
75°
55°
5
81°
59°
6
79°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in New Castle Northwest
New Castle Northwest's May 2026 forecast shows daily high temperatures ranging from 70° to 82°, with overnight lows between 43° and 61°. The average high for May is 75° with an average low of 52°. 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 Northwest. See also: June | July | August.
