S
M
T
W
T
F
S
30
89°
58°
31
89°
57°
1
88°
56°
2
88°
57°
3
87°
56°
4
85°
55°
5
84°
55°
6
85°
54°
7
85°
53°
8
74°
53°
9
82°
52°
10
82°
52°
11
84°
51°
12
83°
52°
13
73°
48°
14
72°
52°
15
81°
51°
16
81°
49°
17
78°
46°
18
70°
47°
19
71°
49°
20
80°
49°
21
80°
48°
22
77°
44°
23
74°
42°
24
71°
44°
25
75°
47°
26
79°
39°
27
75°
43°
28
71°
48°
29
78°
43°
30
77°
45°
1
73°
46°
2
77°
46°
3
77°
44°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Harrisburg
Harrisburg's September 2026 forecast shows daily high temperatures ranging from 70° to 89°, with overnight lows between 39° and 58°. The average high for September is 79° with an average low of 49°. 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 Harrisburg. See also: October | November | December.
