S
M
T
W
T
F
S
26
75°
56°
27
72°
50°
28
61°
44°
29
64°
41°
30
68°
39°
1
67°
33°
2
66°
34°
3
80°
49°
4
89°
50°
5
59°
50°
6
61°
42°
7
73°
51°
8
68°
47°
9
81°
51°
10
67°
43°
11
73°
55°
12
80°
51°
13
75°
54°
14
79°
53°
15
76°
54°
16
75°
53°
17
75°
53°
18
76°
57°
19
74°
54°
20
68°
54°
21
67°
50°
22
67°
51°
23
68°
55°
24
70°
56°
25
71°
59°
26
71°
60°
27
72°
60°
28
73°
58°
29
75°
55°
30
76°
57°
31
79°
62°
1
81°
61°
2
81°
63°
3
82°
63°
4
83°
64°
5
80°
64°
6
79°
63°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Helena
Helena's May 2026 forecast shows daily high temperatures ranging from 61° to 83°, with overnight lows between 42° and 64°. The average high for May is 74° with an average low of 55°. 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 Helena. See also: June | July | August.
