S
M
T
W
T
F
S
26
54°
44°
27
74°
41°
28
67°
53°
29
54°
44°
30
56°
43°
1
48°
40°
2
49°
37°
3
64°
36°
4
76°
50°
5
67°
46°
6
58°
44°
7
58°
40°
8
61°
45°
9
72°
52°
10
63°
47°
11
60°
39°
12
67°
40°
13
61°
46°
14
66°
46°
15
71°
42°
16
79°
55°
17
86°
63°
18
89°
65°
19
88°
67°
20
69°
49°
21
61°
46°
22
62°
51°
23
67°
56°
24
72°
58°
25
74°
53°
26
80°
63°
27
78°
62°
28
75°
55°
29
71°
55°
30
69°
56°
31
71°
54°
1
73°
55°
2
75°
60°
3
76°
59°
4
78°
60°
5
78°
59°
6
77°
57°
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 69° to 80°, with overnight lows between 53° and 63°. The average high for May is 75° with an average low of 58°. 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.
