S
M
T
W
T
F
S
30
75°
63°
31
72°
56°
1
71°
61°
2
75°
61°
3
76°
63°
4
75°
60°
5
69°
59°
6
64°
55°
7
65°
56°
8
66°
57°
9
64°
45°
10
71°
53°
11
69°
52°
12
68°
50°
13
67°
51°
14
65°
49°
15
57°
48°
16
61°
49°
17
62°
48°
18
63°
50°
19
67°
48°
20
59°
48°
21
55°
47°
22
54°
45°
23
53°
46°
24
56°
45°
25
63°
48°
26
64°
47°
27
64°
49°
28
65°
47°
29
62°
46°
30
62°
46°
1
61°
44°
2
55°
44°
3
55°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Riverton
Riverton's September 2026 forecast shows daily high temperatures ranging from 53° to 76°, with overnight lows between 43° and 63°. 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 Riverton. See also: October | November | December.