S
M
T
W
T
F
S
30
66°
39°
31
63°
43°
1
66°
47°
2
69°
48°
3
72°
46°
4
72°
45°
5
70°
42°
6
67°
39°
7
60°
35°
8
57°
36°
9
58°
37°
10
58°
38°
11
57°
35°
12
56°
36°
13
57°
41°
14
55°
35°
15
61°
41°
16
60°
39°
17
60°
43°
18
63°
37°
19
58°
32°
20
53°
32°
21
53°
33°
22
51°
30°
23
51°
31°
24
52°
34°
25
50°
33°
26
51°
30°
27
49°
37°
28
50°
37°
29
50°
33°
30
51°
36°
1
52°
38°
2
49°
38°
3
52°
32°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Assumption
Assumption's September 2026 forecast shows daily high temperatures ranging from 49° to 72°, with overnight lows between 30° and 48°. The average high for September is 58° with an average low of 37°. 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 Assumption. See also: October | November | December.
