S
M
T
W
T
F
S
30
72°
56°
31
70°
54°
1
71°
55°
2
70°
53°
3
72°
54°
4
68°
51°
5
71°
54°
6
73°
56°
7
69°
53°
8
68°
50°
9
69°
56°
10
73°
55°
11
70°
54°
12
69°
52°
13
70°
54°
14
72°
55°
15
71°
54°
16
72°
55°
17
71°
53°
18
68°
48°
19
69°
49°
20
70°
53°
21
71°
54°
22
70°
53°
23
69°
54°
24
70°
54°
25
69°
53°
26
68°
54°
27
68°
51°
28
67°
45°
29
66°
45°
30
67°
46°
1
67°
48°
2
66°
44°
3
61°
44°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Longueil-Sainte-Marie
Longueil-Sainte-Marie's September 2026 forecast shows daily high temperatures ranging from 61° to 73°, with overnight lows between 44° and 56°. The average high for September is 69° with an average low of 52°. 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 Longueil-Sainte-Marie. See also: October | November | December.
