S
M
T
W
T
F
S
26
82°
59°
27
79°
55°
28
73°
46°
29
88°
61°
30
79°
61°
1
70°
55°
2
68°
46°
3
73°
37°
4
80°
40°
5
84°
48°
6
88°
57°
7
79°
64°
8
72°
57°
9
68°
55°
10
83°
62°
11
86°
59°
12
70°
59°
13
72°
59°
14
82°
53°
15
82°
47°
16
89°
51°
17
90°
63°
18
88°
57°
19
88°
55°
20
90°
61°
21
90°
61°
22
90°
66°
23
81°
68°
24
85°
69°
25
82°
69°
26
84°
69°
27
86°
70°
28
87°
70°
29
81°
67°
30
80°
66°
31
78°
63°
1
81°
64°
2
82°
64°
3
82°
64°
4
83°
66°
5
84°
67°
6
85°
65°
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 78° to 87°, with overnight lows between 63° and 70°. The average high for May is 83° with an average low of 67°. 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.
