S
M
T
W
T
F
S
30
92°
60°
31
90°
59°
1
91°
60°
2
92°
61°
3
94°
61°
4
94°
62°
5
93°
63°
6
95°
62°
7
95°
62°
8
94°
62°
9
93°
61°
10
88°
61°
11
87°
62°
12
92°
63°
13
93°
62°
14
93°
62°
15
92°
61°
16
91°
60°
17
89°
61°
18
91°
61°
19
92°
60°
20
91°
60°
21
Hist. Avg.
88°
58°
22
Hist. Avg.
88°
58°
23
Hist. Avg.
87°
57°
24
Hist. Avg.
87°
57°
25
Hist. Avg.
87°
57°
26
Hist. Avg.
86°
57°
27
Hist. Avg.
86°
56°
28
Hist. Avg.
86°
56°
29
Hist. Avg.
86°
56°
30
Hist. Avg.
85°
56°
1
Hist. Avg.
85°
56°
2
Hist. Avg.
84°
55°
3
Hist. Avg.
84°
55°
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 87° to 95°, with overnight lows between 59° and 63°. The average high for September is 92° with an average low of 61°. 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.
