S
M
T
W
T
F
S
30
70°
51°
31
74°
55°
1
78°
60°
2
80°
60°
3
79°
59°
4
69°
49°
5
71°
50°
6
70°
52°
7
73°
53°
8
74°
60°
9
71°
51°
10
71°
50°
11
72°
52°
12
71°
59°
13
69°
50°
14
67°
48°
15
67°
50°
16
68°
50°
17
69°
51°
18
70°
51°
19
76°
54°
20
76°
50°
21
68°
52°
22
68°
50°
23
64°
49°
24
65°
48°
25
63°
45°
26
65°
46°
27
64°
48°
28
66°
53°
29
71°
51°
30
71°
47°
1
Hist. Avg.
66°
48°
2
Hist. Avg.
65°
48°
3
Hist. Avg.
65°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Renton
Renton's September 2026 forecast shows daily high temperatures ranging from 63° to 80°, with overnight lows between 45° and 60°. The average high for September is 70° with an average low of 52°. 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 Renton. See also: October | November | December.
