S
M
T
W
T
F
S
30
72°
55°
31
75°
55°
1
76°
56°
2
76°
55°
3
77°
55°
4
76°
54°
5
76°
54°
6
73°
53°
7
75°
54°
8
75°
49°
9
71°
54°
10
70°
53°
11
73°
51°
12
69°
53°
13
69°
51°
14
68°
49°
15
67°
49°
16
69°
48°
17
74°
52°
18
74°
52°
19
Hist. Avg.
65°
48°
20
Hist. Avg.
65°
48°
21
Hist. Avg.
65°
48°
22
Hist. Avg.
65°
48°
23
Hist. Avg.
65°
48°
24
Hist. Avg.
65°
48°
25
Hist. Avg.
65°
48°
26
Hist. Avg.
65°
47°
27
Hist. Avg.
65°
47°
28
Hist. Avg.
65°
47°
29
Hist. Avg.
65°
47°
30
Hist. Avg.
65°
47°
1
Hist. Avg.
65°
47°
2
Hist. Avg.
65°
47°
3
Hist. Avg.
65°
46°
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 77°, with overnight lows between 48° and 56°. The average high for September is 73° 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.
