S
M
T
W
T
F
S
30
76°
64°
31
76°
66°
1
81°
70°
2
81°
66°
3
79°
60°
4
76°
59°
5
74°
60°
6
77°
61°
7
74°
59°
8
76°
62°
9
77°
63°
10
78°
55°
11
74°
60°
12
76°
59°
13
77°
60°
14
78°
60°
15
78°
59°
16
77°
59°
17
73°
58°
18
77°
60°
19
75°
60°
20
76°
59°
21
75°
59°
22
76°
60°
23
76°
57°
24
70°
56°
25
65°
54°
26
66°
52°
27
71°
55°
28
73°
56°
29
73°
56°
30
72°
55°
1
73°
56°
2
73°
56°
3
71°
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 65° to 81°, with overnight lows between 52° and 70°. The average high for September is 75° with an average low of 59°. 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.
