S
M
T
W
T
F
S
26
82°
59°
27
74°
53°
28
72°
47°
29
83°
57°
30
78°
63°
1
70°
59°
2
61°
49°
3
73°
45°
4
80°
45°
5
83°
50°
6
87°
58°
7
79°
63°
8
74°
53°
9
74°
58°
10
87°
62°
11
86°
59°
12
73°
55°
13
80°
52°
14
82°
58°
15
81°
46°
16
87°
51°
17
91°
68°
18
91°
65°
19
92°
61°
20
94°
63°
21
94°
65°
22
92°
68°
23
84°
68°
24
85°
69°
25
87°
69°
26
84°
69°
27
83°
68°
28
88°
68°
29
81°
67°
30
76°
63°
31
76°
61°
1
76°
60°
2
83°
61°
3
77°
62°
4
77°
63°
5
79°
62°
6
83°
64°
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 76° to 88°, with overnight lows between 60° and 69°. The average high for May is 80° with an average low of 64°. 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.
