S
M
T
W
T
F
S
30
95°
69°
31
95°
70°
1
94°
69°
2
95°
70°
3
95°
70°
4
94°
71°
5
94°
69°
6
93°
65°
7
90°
61°
8
86°
61°
9
85°
63°
10
90°
67°
11
91°
66°
12
91°
65°
13
84°
66°
14
83°
68°
15
91°
58°
16
91°
57°
17
81°
56°
18
79°
57°
19
79°
55°
20
80°
54°
21
79°
56°
22
79°
54°
23
80°
54°
24
80°
57°
25
81°
62°
26
81°
62°
27
83°
63°
28
85°
62°
29
85°
53°
30
82°
53°
1
78°
54°
2
77°
51°
3
76°
53°
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 76° to 95°, with overnight lows between 51° and 71°. The average high for September is 86° with an average low of 61°. 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.
