S
M
T
W
T
F
S
26
63°
46°
27
81°
52°
28
82°
34°
29
60°
45°
30
64°
43°
1
48°
37°
2
73°
32°
3
61°
34°
4
75°
57°
5
64°
45°
6
53°
39°
7
54°
40°
8
61°
50°
9
68°
53°
10
66°
46°
11
60°
40°
12
61°
45°
13
65°
52°
14
64°
48°
15
67°
51°
16
71°
52°
17
75°
53°
18
72°
56°
19
73°
55°
20
76°
51°
21
71°
51°
22
67°
47°
23
65°
47°
24
67°
49°
25
67°
51°
26
66°
49°
27
67°
50°
28
68°
50°
29
69°
51°
30
70°
54°
31
76°
58°
1
70°
54°
2
72°
53°
3
73°
58°
4
75°
58°
5
77°
61°
6
80°
62°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Lewistown
Lewistown's May 2026 forecast shows daily high temperatures ranging from 53° to 80°, with overnight lows between 39° and 62°. The average high for May is 68° with an average low of 51°. 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 Lewistown. See also: June | July | August.
