S
M
T
W
T
F
S
30
62°
52°
31
63°
53°
1
62°
54°
2
64°
52°
3
63°
50°
4
61°
51°
5
61°
53°
6
62°
51°
7
64°
53°
8
65°
50°
9
65°
50°
10
64°
51°
11
60°
52°
12
62°
48°
13
64°
51°
14
64°
49°
15
63°
45°
16
59°
50°
17
63°
48°
18
63°
47°
19
62°
53°
20
63°
52°
21
63°
52°
22
61°
51°
23
59°
50°
24
60°
51°
25
58°
51°
26
60°
50°
27
61°
51°
28
60°
49°
29
60°
48°
30
59°
48°
1
Hist. Avg.
61°
49°
2
Hist. Avg.
61°
49°
3
Hist. Avg.
61°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Markham
Markham's September 2026 forecast shows daily high temperatures ranging from 58° to 65°, with overnight lows between 45° and 54°. The average high for September is 62° with an average low of 51°. 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 Markham. See also: October | November | December.
