S
M
T
W
T
F
S
26
54°
35°
27
60°
35°
28
62°
37°
29
61°
36°
30
52°
38°
1
67°
29°
2
74°
34°
3
75°
42°
4
72°
43°
5
44°
32°
6
44°
31°
7
71°
30°
8
75°
44°
9
78°
47°
10
72°
43°
11
88°
46°
12
77°
54°
13
92°
46°
14
88°
58°
15
85°
50°
16
81°
56°
17
70°
44°
18
45°
35°
19
53°
43°
20
64°
43°
21
68°
44°
22
67°
46°
23
78°
49°
24
83°
49°
25
84°
52°
26
82°
51°
27
82°
52°
28
83°
50°
29
81°
52°
30
82°
53°
31
80°
47°
1
73°
51°
2
73°
49°
3
72°
42°
4
75°
47°
5
78°
48°
6
79°
48°
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 45° to 84°, with overnight lows between 35° and 53°. The average high for May is 74° with an average low of 48°. 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.
