S
M
T
W
T
F
S
26
72°
54°
27
72°
48°
28
57°
45°
29
59°
39°
30
55°
36°
1
57°
36°
2
63°
32°
3
75°
46°
4
81°
43°
5
61°
39°
6
57°
36°
7
68°
36°
8
75°
48°
9
73°
43°
10
72°
36°
11
75°
39°
12
79°
59°
13
75°
48°
14
79°
48°
15
88°
55°
16
81°
59°
17
82°
63°
18
80°
50°
19
63°
45°
20
66°
49°
21
62°
53°
22
66°
54°
23
73°
57°
24
79°
62°
25
83°
61°
26
81°
62°
27
82°
63°
28
80°
60°
29
79°
58°
30
80°
59°
31
77°
57°
1
82°
62°
2
78°
62°
3
73°
58°
4
73°
58°
5
78°
63°
6
79°
63°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Johnston
Johnston's May 2026 forecast shows daily high temperatures ranging from 62° to 83°, with overnight lows between 45° and 63°. The average high for May is 76° 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 Johnston. See also: June | July | August.
