S
M
T
W
T
F
S
30
86°
64°
31
86°
64°
1
87°
63°
2
87°
63°
3
85°
62°
4
85°
61°
5
86°
63°
6
87°
63°
7
87°
62°
8
88°
63°
9
87°
63°
10
85°
61°
11
86°
63°
12
87°
63°
13
87°
62°
14
76°
51°
15
74°
56°
16
76°
58°
17
75°
53°
18
85°
60°
19
85°
58°
20
84°
51°
21
77°
50°
22
72°
52°
23
69°
55°
24
72°
53°
25
72°
55°
26
78°
56°
27
80°
56°
28
82°
55°
29
82°
56°
30
81°
48°
1
80°
43°
2
70°
42°
3
66°
43°
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 66° to 88°, with overnight lows between 42° and 64°. The average high for September is 81° with an average low of 57°. 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.
