S
M
T
W
T
F
S
30
67°
53°
31
73°
59°
1
74°
59°
2
73°
52°
3
74°
51°
4
65°
53°
5
66°
52°
6
65°
54°
7
65°
56°
8
71°
53°
9
71°
55°
10
70°
55°
11
71°
50°
12
65°
47°
13
63°
47°
14
63°
48°
15
65°
54°
16
69°
54°
17
68°
56°
18
69°
55°
19
70°
46°
20
67°
47°
21
60°
51°
22
66°
51°
23
66°
54°
24
67°
53°
25
64°
54°
26
66°
54°
27
68°
52°
28
67°
52°
29
61°
47°
30
59°
43°
1
58°
44°
2
57°
43°
3
56°
44°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Illertissen
Illertissen's September 2026 forecast shows daily high temperatures ranging from 56° to 74°, with overnight lows between 43° and 59°. The average high for September is 66° 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 Illertissen. See also: October | November | December.
