S
M
T
W
T
F
S
26
84°
62°
27
84°
72°
28
85°
72°
29
74°
59°
30
66°
57°
1
64°
52°
2
75°
45°
3
81°
45°
4
80°
53°
5
83°
65°
6
74°
52°
7
72°
49°
8
80°
59°
9
84°
64°
10
82°
61°
11
77°
49°
12
80°
54°
13
85°
57°
14
84°
61°
15
85°
62°
16
88°
63°
17
86°
64°
18
86°
65°
19
85°
64°
20
84°
65°
21
83°
60°
22
79°
64°
23
79°
64°
24
81°
63°
25
80°
65°
26
79°
65°
27
80°
64°
28
81°
65°
29
80°
65°
30
80°
64°
31
81°
62°
1
82°
62°
2
84°
64°
3
84°
66°
4
82°
67°
5
82°
67°
6
84°
68°
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 77° to 88°, with overnight lows between 49° and 68°. The average high for May is 82° with an average low of 63°. 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.
