S
M
T
W
T
F
S
30
86°
64°
31
83°
70°
1
89°
69°
2
89°
69°
3
87°
67°
4
81°
60°
5
79°
58°
6
78°
57°
7
81°
60°
8
78°
59°
9
80°
59°
10
75°
55°
11
76°
52°
12
72°
51°
13
74°
49°
14
76°
56°
15
74°
56°
16
71°
55°
17
72°
51°
18
68°
46°
19
69°
49°
20
74°
54°
21
76°
54°
22
76°
53°
23
77°
54°
24
76°
53°
25
75°
51°
26
74°
51°
27
75°
52°
28
74°
52°
29
75°
51°
30
70°
46°
1
67°
44°
2
69°
47°
3
72°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Johnstown
Johnstown's September 2026 forecast shows daily high temperatures ranging from 67° to 89°, with overnight lows between 44° and 70°. The average high for September is 76° with an average low of 55°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Johnstown. See also: October | November | December.
