S
M
T
W
T
F
S
30
75°
51°
31
76°
51°
1
75°
56°
2
74°
59°
3
74°
58°
4
72°
54°
5
73°
50°
6
72°
53°
7
74°
52°
8
73°
53°
9
74°
50°
10
76°
50°
11
76°
53°
12
71°
52°
13
72°
58°
14
72°
51°
15
69°
49°
16
Hist. Avg.
78°
50°
17
Hist. Avg.
77°
50°
18
Hist. Avg.
77°
50°
19
Hist. Avg.
77°
49°
20
Hist. Avg.
76°
49°
21
Hist. Avg.
76°
49°
22
Hist. Avg.
76°
49°
23
Hist. Avg.
76°
48°
24
Hist. Avg.
75°
48°
25
Hist. Avg.
75°
48°
26
Hist. Avg.
74°
48°
27
Hist. Avg.
74°
47°
28
Hist. Avg.
74°
47°
29
Hist. Avg.
73°
47°
30
Hist. Avg.
73°
47°
1
Hist. Avg.
72°
46°
2
Hist. Avg.
72°
46°
3
Hist. Avg.
71°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Markham
Markham's September 2026 forecast shows daily high temperatures ranging from 69° to 76°, with overnight lows between 49° and 59°. 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 Markham. See also: October | November | December.
