S
M
T
W
T
F
S
30
75°
52°
31
79°
56°
1
81°
51°
2
75°
50°
3
74°
51°
4
75°
56°
5
78°
58°
6
80°
58°
7
80°
57°
8
73°
56°
9
74°
57°
10
79°
56°
11
74°
56°
12
77°
55°
13
74°
54°
14
71°
47°
15
69°
49°
16
70°
48°
17
70°
52°
18
73°
51°
19
76°
53°
20
77°
54°
21
73°
48°
22
74°
50°
23
69°
52°
24
73°
50°
25
73°
44°
26
67°
43°
27
Hist. Avg.
67°
49°
28
Hist. Avg.
66°
48°
29
Hist. Avg.
66°
48°
30
Hist. Avg.
66°
48°
1
Hist. Avg.
65°
48°
2
Hist. Avg.
65°
47°
3
Hist. Avg.
64°
47°
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 67° to 81°, with overnight lows between 43° and 58°. The average high for September is 74° with an average low of 52°. 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.
