S
M
T
W
T
F
S
26
49°
40°
27
64°
38°
28
58°
46°
29
55°
47°
30
47°
35°
1
53°
34°
2
44°
32°
3
53°
29°
4
68°
43°
5
72°
55°
6
63°
43°
7
56°
36°
8
57°
38°
9
66°
52°
10
61°
44°
11
56°
34°
12
60°
46°
13
61°
45°
14
57°
43°
15
64°
44°
16
69°
49°
17
74°
54°
18
76°
56°
19
73°
52°
20
73°
53°
21
74°
54°
22
77°
47°
23
76°
52°
24
75°
51°
25
76°
52°
26
77°
54°
27
78°
54°
28
77°
53°
29
78°
55°
30
78°
55°
31
77°
54°
1
73°
49°
2
70°
46°
3
72°
54°
4
75°
56°
5
72°
55°
6
76°
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 56° to 78°, with overnight lows between 34° and 56°. The average high for May is 71° 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.
