S
M
T
W
T
F
S
30
82°
62°
31
87°
68°
1
84°
69°
2
92°
70°
3
92°
70°
4
83°
67°
5
84°
66°
6
78°
58°
7
81°
60°
8
83°
66°
9
87°
67°
10
74°
58°
11
76°
58°
12
81°
63°
13
83°
64°
14
79°
60°
15
73°
58°
16
74°
56°
17
75°
57°
18
77°
57°
19
73°
55°
20
71°
51°
21
78°
56°
22
70°
55°
23
73°
55°
24
77°
54°
25
78°
57°
26
78°
55°
27
77°
55°
28
77°
56°
29
78°
56°
30
78°
55°
1
77°
55°
2
74°
46°
3
63°
42°
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 63° to 87°, with overnight lows between 42° and 67°. The average high for September is 76° with an average low of 57°. 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.
