S
M
T
W
T
F
S
30
72°
63°
31
72°
61°
1
72°
57°
2
70°
55°
3
72°
61°
4
75°
59°
5
68°
50°
6
71°
57°
7
81°
59°
8
66°
51°
9
61°
47°
10
62°
48°
11
61°
50°
12
64°
49°
13
65°
52°
14
66°
53°
15
67°
52°
16
62°
49°
17
60°
48°
18
62°
49°
19
62°
52°
20
64°
53°
21
64°
54°
22
65°
55°
23
65°
54°
24
66°
54°
25
66°
50°
26
63°
46°
27
61°
46°
28
61°
45°
29
60°
45°
30
60°
52°
1
62°
48°
2
58°
47°
3
62°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Altena
Altena's September 2026 forecast shows daily high temperatures ranging from 58° to 81°, with overnight lows between 45° and 59°. The average high for September is 64° with an average low of 51°. 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 Altena. See also: October | November | December.