S
M
T
W
T
F
S
30
85°
62°
31
84°
68°
1
88°
73°
2
92°
71°
3
89°
68°
4
81°
67°
5
79°
65°
6
79°
59°
7
79°
58°
8
83°
59°
9
88°
71°
10
76°
62°
11
78°
62°
12
78°
66°
13
82°
66°
14
83°
70°
15
86°
66°
16
77°
59°
17
76°
60°
18
74°
60°
19
66°
52°
20
66°
54°
21
67°
53°
22
67°
53°
23
72°
58°
24
76°
57°
25
70°
53°
26
72°
55°
27
75°
57°
28
74°
54°
29
69°
52°
30
73°
57°
1
71°
53°
2
66°
52°
3
72°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Heidelberg
Heidelberg's September 2026 forecast shows daily high temperatures ranging from 66° to 88°, with overnight lows between 52° and 71°. The average high for September is 74° with an average low of 58°. 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 Heidelberg. See also: October | November | December.
