S
M
T
W
T
F
S
30
70°
50°
31
68°
49°
1
68°
48°
2
69°
51°
3
70°
52°
4
68°
52°
5
68°
50°
6
67°
51°
7
65°
49°
8
66°
47°
9
65°
48°
10
67°
52°
11
64°
47°
12
66°
46°
13
67°
46°
14
70°
53°
15
69°
54°
16
66°
53°
17
68°
49°
18
71°
45°
19
72°
51°
20
72°
52°
21
71°
45°
22
69°
47°
23
63°
43°
24
62°
42°
25
61°
46°
26
66°
41°
27
64°
41°
28
58°
40°
29
56°
41°
30
57°
43°
1
58°
40°
2
Hist. Avg.
60°
43°
3
Hist. Avg.
60°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Montreal–Trudeau
Montreal–Trudeau's September 2026 forecast shows daily high temperatures ranging from 56° to 72°, with overnight lows between 40° and 54°. The average high for September is 66° with an average low of 47°. 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 Montreal–Trudeau. See also: October | November | December.
