S
M
T
W
T
F
S
30
88°
56°
31
89°
55°
1
87°
54°
2
89°
55°
3
91°
55°
4
85°
54°
5
86°
55°
6
85°
53°
7
90°
55°
8
91°
55°
9
91°
56°
10
90°
56°
11
91°
55°
12
87°
54°
13
84°
55°
14
83°
52°
15
84°
53°
16
87°
54°
17
89°
55°
18
90°
54°
19
89°
53°
20
89°
53°
21
88°
52°
22
89°
53°
23
85°
52°
24
84°
52°
25
87°
51°
26
87°
52°
27
86°
52°
28
86°
51°
29
83°
48°
30
85°
51°
1
81°
45°
2
77°
42°
3
77°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Clearlake Riviera
Clearlake Riviera's September 2026 forecast shows daily high temperatures ranging from 77° to 91°, with overnight lows between 42° and 56°. The average high for September is 87° 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 Clearlake Riviera. See also: October | November | December.
