S
M
T
W
T
F
S
30
75°
56°
31
73°
56°
1
68°
63°
2
67°
60°
3
78°
61°
4
78°
59°
5
72°
58°
6
70°
53°
7
N/A
8
77°
55°
9
76°
67°
10
77°
53°
11
71°
45°
12
75°
55°
13
77°
56°
14
74°
54°
15
73°
58°
16
75°
49°
17
67°
49°
18
65°
50°
19
64°
45°
20
68°
47°
21
67°
46°
22
63°
50°
23
65°
50°
24
66°
49°
25
68°
50°
26
70°
46°
27
63°
42°
28
66°
48°
29
70°
49°
30
71°
49°
1
70°
48°
2
69°
49°
3
68°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Johnstown
Johnstown's September 2026 forecast shows daily high temperatures ranging from 63° to 77°, with overnight lows between 42° and 67°. The average high for September is 70° with an average low of 50°. 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.
