S
M
T
W
T
F
S
30
87°
62°
31
88°
62°
1
88°
59°
2
82°
60°
3
81°
65°
4
85°
66°
5
83°
62°
6
87°
57°
7
80°
63°
8
84°
63°
9
79°
59°
10
86°
63°
11
79°
61°
12
84°
55°
13
77°
54°
14
76°
53°
15
76°
54°
16
77°
56°
17
80°
60°
18
82°
61°
19
82°
61°
20
76°
60°
21
81°
61°
22
82°
59°
23
83°
52°
24
79°
51°
25
71°
49°
26
73°
50°
27
Hist. Avg.
76°
52°
28
Hist. Avg.
75°
52°
29
Hist. Avg.
75°
52°
30
Hist. Avg.
75°
51°
1
Hist. Avg.
74°
51°
2
Hist. Avg.
74°
51°
3
Hist. Avg.
74°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Montreal
Montreal's September 2026 forecast shows daily high temperatures ranging from 71° to 88°, with overnight lows between 49° and 66°. The average high for September is 81° with an average low of 59°. 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.
