S
M
T
W
T
F
S
30
75°
59°
31
72°
54°
1
64°
48°
2
64°
43°
3
63°
55°
4
66°
55°
5
64°
55°
6
65°
52°
7
72°
55°
8
70°
52°
9
71°
55°
10
74°
56°
11
73°
59°
12
67°
57°
13
72°
54°
14
70°
52°
15
72°
51°
16
74°
56°
17
71°
57°
18
68°
55°
19
68°
54°
20
64°
53°
21
63°
54°
22
63°
55°
23
64°
55°
24
64°
56°
25
66°
55°
26
67°
55°
27
70°
54°
28
69°
55°
29
66°
56°
30
64°
56°
1
64°
55°
2
65°
53°
3
67°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Clarkson
Clarkson's September 2026 forecast shows daily high temperatures ranging from 63° to 74°, with overnight lows between 51° and 59°. The average high for September is 68° with an average low of 55°. 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 Clarkson. See also: October | November | December.
