S
M
T
W
T
F
S
30
79°
60°
31
82°
64°
1
82°
57°
2
83°
56°
3
75°
57°
4
76°
58°
5
77°
64°
6
81°
61°
7
82°
57°
8
75°
60°
9
74°
62°
10
77°
62°
11
79°
61°
12
78°
60°
13
73°
60°
14
72°
54°
15
75°
54°
16
72°
53°
17
72°
56°
18
73°
57°
19
76°
58°
20
71°
59°
21
75°
57°
22
74°
51°
23
72°
56°
24
69°
58°
25
74°
54°
26
67°
53°
27
70°
55°
28
Hist. Avg.
70°
52°
29
Hist. Avg.
70°
51°
30
Hist. Avg.
70°
51°
1
Hist. Avg.
69°
51°
2
Hist. Avg.
69°
50°
3
Hist. Avg.
68°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Riverside
Riverside's September 2026 forecast shows daily high temperatures ranging from 67° to 83°, with overnight lows between 51° and 64°. The average high for September is 75° with an average low of 58°. 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 Riverside. See also: October | November | December.
