S
M
T
W
T
F
S
30
76°
59°
31
76°
58°
1
68°
56°
2
67°
55°
3
67°
54°
4
68°
52°
5
72°
57°
6
75°
57°
7
75°
56°
8
74°
57°
9
75°
57°
10
72°
56°
11
74°
56°
12
74°
55°
13
72°
57°
14
65°
42°
15
63°
44°
16
64°
44°
17
66°
46°
18
67°
44°
19
63°
48°
20
63°
49°
21
69°
51°
22
70°
48°
23
69°
41°
24
64°
39°
25
59°
45°
26
67°
48°
27
68°
49°
28
68°
42°
29
62°
37°
30
57°
37°
1
57°
45°
2
62°
45°
3
60°
38°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Montreal
Montreal's September 2026 forecast shows daily high temperatures ranging from 57° to 76°, with overnight lows between 37° and 59°. The average high for September is 68° with an average low of 49°. 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. See also: October | November | December.
