S
M
T
W
T
F
S
26
64°
34°
27
68°
41°
28
60°
41°
29
47°
37°
30
47°
34°
1
45°
31°
2
49°
33°
3
53°
39°
4
66°
42°
5
54°
32°
6
53°
36°
7
47°
31°
8
49°
35°
9
53°
35°
10
57°
36°
11
56°
36°
12
57°
38°
13
59°
39°
14
57°
40°
15
58°
41°
16
68°
48°
17
69°
47°
18
62°
44°
19
65°
48°
20
66°
48°
21
67°
42°
22
61°
39°
23
59°
40°
24
60°
39°
25
60°
39°
26
61°
40°
27
61°
40°
28
62°
41°
29
62°
41°
30
64°
49°
31
67°
47°
1
65°
47°
2
66°
50°
3
72°
52°
4
71°
52°
5
73°
54°
6
74°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in St. Helen
St. Helen's May 2026 forecast shows daily high temperatures ranging from 47° to 74°, with overnight lows between 31° and 55°. The average high for May is 61° with an average low of 42°. 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 St. Helen. See also: June | July | August.
