S
M
T
W
T
F
S
30
98°
66°
31
100°
70°
1
100°
72°
2
96°
72°
3
96°
72°
4
96°
72°
5
94°
71°
6
96°
72°
7
96°
71°
8
97°
70°
9
96°
72°
10
93°
69°
11
93°
70°
12
92°
68°
13
91°
67°
14
90°
66°
15
86°
61°
16
83°
65°
17
86°
65°
18
85°
65°
19
87°
65°
20
88°
64°
21
88°
65°
22
87°
65°
23
88°
64°
24
87°
64°
25
87°
63°
26
82°
62°
27
78°
57°
28
77°
53°
29
76°
52°
30
76°
52°
1
80°
55°
2
82°
56°
3
74°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Lanark
Lanark's September 2026 forecast shows daily high temperatures ranging from 74° to 97°, with overnight lows between 52° and 72°. The average high for September is 88° with an average low of 64°. 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 Lanark. See also: October | November | December.
