S
M
T
W
T
F
S
26
62°
41°
27
69°
41°
28
65°
40°
29
62°
43°
30
54°
44°
1
63°
43°
2
54°
46°
3
54°
38°
4
70°
40°
5
80°
49°
6
71°
55°
7
63°
47°
8
62°
37°
9
61°
37°
10
72°
51°
11
61°
43°
12
64°
41°
13
67°
46°
14
61°
45°
15
60°
43°
16
77°
43°
17
88°
57°
18
83°
57°
19
92°
66°
20
89°
67°
21
68°
49°
22
65°
46°
23
65°
45°
24
55°
48°
25
74°
53°
26
81°
53°
27
88°
59°
28
73°
51°
29
74°
52°
30
60°
44°
31
70°
46°
1
63°
48°
2
72°
50°
3
77°
56°
4
75°
55°
5
74°
57°
6
73°
57°
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 60° to 88°, with overnight lows between 44° and 59°. The average high for May is 73° with an average low of 52°. 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.
