S
M
T
W
T
F
S
30
81°
66°
31
89°
59°
1
86°
53°
2
86°
61°
3
87°
67°
4
90°
63°
5
84°
68°
6
83°
69°
7
81°
68°
8
83°
59°
9
78°
55°
10
75°
54°
11
75°
57°
12
77°
61°
13
78°
55°
14
80°
58°
15
80°
57°
16
71°
48°
17
74°
55°
18
75°
53°
19
74°
52°
20
75°
53°
21
69°
52°
22
72°
50°
23
73°
53°
24
74°
52°
25
72°
47°
26
61°
41°
27
60°
39°
28
58°
38°
29
69°
40°
30
59°
38°
1
58°
45°
2
57°
43°
3
58°
40°
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 57° to 90°, with overnight lows between 38° and 69°. The average high for September is 73° 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 Clear Lake. See also: October | November | December.
