S
M
T
W
T
F
S
26
57°
44°
27
56°
43°
28
57°
42°
29
56°
42°
30
58°
41°
1
59°
48°
2
67°
47°
3
60°
46°
4
59°
43°
5
60°
41°
6
61°
43°
7
60°
44°
8
59°
45°
9
61°
46°
10
60°
42°
11
62°
46°
12
62°
48°
13
64°
45°
14
63°
46°
15
63°
44°
16
64°
44°
17
65°
53°
18
72°
53°
19
67°
52°
20
68°
51°
21
68°
51°
22
69°
47°
23
68°
49°
24
69°
48°
25
68°
49°
26
72°
54°
27
75°
53°
28
76°
55°
29
76°
56°
30
75°
56°
31
70°
55°
1
70°
56°
2
71°
57°
3
70°
54°
4
77°
55°
5
78°
58°
6
77°
59°
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 56° to 78°, with overnight lows between 41° and 59°. The average high for May is 66° with an average low of 49°. 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.
