S
M
T
W
T
F
S
30
79°
54°
31
78°
55°
1
77°
58°
2
77°
59°
3
78°
55°
4
77°
52°
5
76°
53°
6
74°
53°
7
75°
52°
8
76°
51°
9
77°
53°
10
76°
50°
11
75°
50°
12
74°
52°
13
75°
51°
14
74°
54°
15
78°
53°
16
78°
55°
17
79°
56°
18
79°
55°
19
72°
47°
20
79°
48°
21
71°
47°
22
Hist. Avg.
74°
49°
23
Hist. Avg.
74°
49°
24
Hist. Avg.
74°
48°
25
Hist. Avg.
73°
48°
26
Hist. Avg.
73°
48°
27
Hist. Avg.
72°
47°
28
Hist. Avg.
72°
47°
29
Hist. Avg.
72°
46°
30
Hist. Avg.
71°
46°
1
Hist. Avg.
71°
46°
2
Hist. Avg.
70°
45°
3
Hist. Avg.
70°
45°
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 71° to 79°, with overnight lows between 47° and 59°. The average high for September is 76° with an average low of 53°. 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.
