S
M
T
W
T
F
S
30
80°
62°
31
80°
62°
1
83°
61°
2
84°
60°
3
83°
53°
4
76°
56°
5
75°
60°
6
82°
58°
7
79°
52°
8
74°
51°
9
73°
58°
10
74°
59°
11
81°
58°
12
81°
59°
13
80°
58°
14
81°
53°
15
80°
53°
16
71°
54°
17
72°
48°
18
71°
48°
19
71°
45°
20
69°
45°
21
69°
47°
22
70°
53°
23
72°
50°
24
76°
54°
25
76°
54°
26
75°
53°
27
77°
54°
28
75°
50°
29
74°
49°
30
70°
49°
1
71°
50°
2
75°
51°
3
74°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Rio
Rio's September 2026 forecast shows daily high temperatures ranging from 69° to 84°, with overnight lows between 45° and 62°. The average high for September is 76° with an average low of 54°. 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 Rio. See also: October | November | December.
