S
M
T
W
T
F
S
30
87°
68°
31
89°
67°
1
90°
65°
2
86°
60°
3
85°
61°
4
85°
63°
5
86°
63°
6
86°
64°
7
87°
62°
8
85°
61°
9
85°
58°
10
84°
59°
11
84°
60°
12
86°
63°
13
88°
60°
14
87°
59°
15
86°
65°
16
85°
65°
17
81°
64°
18
81°
65°
19
82°
65°
20
81°
64°
21
81°
64°
22
85°
63°
23
84°
64°
24
84°
64°
25
87°
63°
26
87°
62°
27
86°
59°
28
85°
58°
29
82°
59°
30
82°
62°
1
84°
63°
2
86°
61°
3
85°
58°
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 81° to 90°, with overnight lows between 58° and 68°. The average high for September is 85° 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.
