S
M
T
W
T
F
S
26
56°
41°
27
71°
36°
28
56°
42°
29
58°
48°
30
61°
43°
1
62°
36°
2
55°
41°
3
60°
42°
4
73°
35°
5
81°
50°
6
68°
53°
7
64°
49°
8
64°
39°
9
62°
47°
10
67°
46°
11
63°
45°
12
67°
37°
13
67°
51°
14
55°
47°
15
70°
47°
16
81°
44°
17
85°
62°
18
93°
59°
19
92°
65°
20
87°
63°
21
65°
53°
22
67°
50°
23
52°
46°
24
60°
49°
25
76°
59°
26
81°
65°
27
80°
64°
28
76°
54°
29
76°
51°
30
70°
49°
31
72°
53°
1
75°
54°
2
73°
56°
3
76°
58°
4
77°
59°
5
79°
58°
6
80°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Johnstown
Johnstown's May 2026 forecast shows daily high temperatures ranging from 70° to 81°, with overnight lows between 49° and 65°. The average high for May is 76° with an average low of 57°. 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 Johnstown. See also: June | July | August.
