S
M
T
W
T
F
S
30
83°
59°
31
84°
60°
1
80°
59°
2
79°
56°
3
79°
55°
4
78°
53°
5
79°
53°
6
83°
55°
7
81°
56°
8
83°
55°
9
81°
53°
10
82°
53°
11
83°
55°
12
83°
59°
13
82°
58°
14
83°
58°
15
83°
57°
16
82°
58°
17
81°
56°
18
81°
56°
19
80°
55°
20
80°
54°
21
78°
55°
22
79°
51°
23
75°
54°
24
73°
54°
25
Hist. Avg.
78°
53°
26
Hist. Avg.
77°
53°
27
Hist. Avg.
77°
52°
28
Hist. Avg.
77°
52°
29
Hist. Avg.
76°
51°
30
Hist. Avg.
76°
51°
1
Hist. Avg.
76°
51°
2
Hist. Avg.
75°
50°
3
Hist. Avg.
75°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Allegheny
Allegheny's September 2026 forecast shows daily high temperatures ranging from 73° to 84°, with overnight lows between 51° and 60°. The average high for September is 81° with an average low of 56°. 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 Allegheny. See also: October | November | December.
