S
M
T
W
T
F
S
26
60°
44°
27
74°
44°
28
71°
54°
29
58°
45°
30
54°
39°
1
48°
33°
2
51°
33°
3
58°
45°
4
72°
57°
5
68°
51°
6
57°
43°
7
53°
37°
8
57°
44°
9
63°
47°
10
64°
47°
11
65°
50°
12
67°
52°
13
66°
50°
14
64°
49°
15
70°
53°
16
66°
49°
17
69°
54°
18
74°
56°
19
76°
56°
20
74°
57°
21
77°
57°
22
76°
56°
23
77°
56°
24
72°
51°
25
69°
52°
26
76°
58°
27
77°
56°
28
73°
57°
29
73°
55°
30
71°
54°
31
76°
55°
1
71°
51°
2
74°
58°
3
75°
52°
4
71°
51°
5
71°
51°
6
72°
52°
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 48° to 77°, with overnight lows between 33° and 58°. The average high for May is 68° with an average low of 51°. 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.
