S
M
T
W
T
F
S
30
86°
68°
31
91°
64°
1
90°
61°
2
88°
65°
3
86°
70°
4
88°
67°
5
85°
67°
6
84°
66°
7
85°
67°
8
76°
57°
9
78°
50°
10
76°
58°
11
79°
60°
12
74°
49°
13
65°
54°
14
64°
50°
15
66°
48°
16
70°
52°
17
66°
47°
18
64°
47°
19
67°
45°
20
66°
48°
21
69°
47°
22
70°
53°
23
70°
53°
24
72°
52°
25
70°
52°
26
69°
51°
27
71°
53°
28
70°
53°
29
67°
52°
30
68°
50°
1
61°
44°
2
56°
41°
3
56°
37°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Clear Lake
Clear Lake's September 2026 forecast shows daily high temperatures ranging from 56° to 79°, with overnight lows between 37° and 60°. The average high for September is 68° with an average low of 50°. 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 Clear Lake. See also: October | November | December.
