S
M
T
W
T
F
S
30
106°
72°
31
105°
76°
1
103°
75°
2
102°
76°
3
101°
76°
4
102°
76°
5
100°
74°
6
103°
73°
7
103°
75°
8
102°
77°
9
101°
76°
10
102°
74°
11
94°
68°
12
90°
65°
13
91°
65°
14
87°
62°
15
88°
66°
16
89°
67°
17
89°
67°
18
88°
66°
19
89°
66°
20
89°
65°
21
88°
66°
22
88°
66°
23
87°
65°
24
87°
64°
25
86°
64°
26
87°
63°
27
88°
64°
28
87°
63°
29
86°
62°
30
87°
63°
1
87°
63°
2
86°
62°
3
86°
62°
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 86° to 103°, with overnight lows between 62° and 77°. The average high for September is 92° with an average low of 68°. 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.
