S
M
T
W
T
F
S
30
85°
50°
31
84°
54°
1
80°
56°
2
86°
55°
3
84°
51°
4
79°
51°
5
77°
50°
6
80°
53°
7
82°
53°
8
83°
44°
9
76°
53°
10
78°
52°
11
75°
51°
12
79°
52°
13
80°
47°
14
81°
45°
15
72°
43°
16
72°
44°
17
73°
47°
18
73°
40°
19
69°
40°
20
70°
41°
21
70°
45°
22
74°
49°
23
78°
48°
24
78°
48°
25
76°
40°
26
73°
46°
27
70°
38°
28
71°
35°
29
63°
39°
30
64°
48°
1
70°
45°
2
74°
47°
3
75°
34°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in American Falls
American Falls's September 2026 forecast shows daily high temperatures ranging from 63° to 86°, with overnight lows between 34° and 56°. The average high for September is 76° with an average low of 47°. 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 American Falls. See also: October | November | December.
