S
M
T
W
T
F
S
30
93°
69°
31
92°
69°
1
93°
68°
2
93°
68°
3
92°
70°
4
91°
68°
5
91°
65°
6
92°
59°
7
85°
58°
8
84°
60°
9
84°
61°
10
88°
64°
11
90°
63°
12
91°
64°
13
89°
66°
14
91°
65°
15
90°
60°
16
89°
61°
17
88°
63°
18
89°
65°
19
88°
62°
20
88°
58°
21
86°
63°
22
81°
61°
23
78°
58°
24
80°
62°
25
80°
59°
26
83°
57°
27
80°
58°
28
80°
61°
29
79°
55°
30
78°
60°
1
78°
63°
2
84°
60°
3
78°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Lake Riverside
Lake Riverside's September 2026 forecast shows daily high temperatures ranging from 78° to 93°, with overnight lows between 55° and 70°. The average high for September is 86° with an average low of 62°. 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 Lake Riverside. See also: October | November | December.
