S
M
T
W
T
F
S
30
81°
46°
31
80°
42°
1
78°
52°
2
77°
51°
3
79°
42°
4
80°
46°
5
81°
47°
6
75°
49°
7
78°
42°
8
83°
36°
9
87°
39°
10
89°
44°
11
84°
52°
12
87°
58°
13
82°
39°
14
77°
41°
15
79°
49°
16
80°
48°
17
81°
51°
18
83°
47°
19
77°
48°
20
77°
48°
21
70°
46°
22
73°
44°
23
70°
43°
24
74°
39°
25
65°
37°
26
67°
44°
27
71°
44°
28
69°
43°
29
70°
43°
30
73°
42°
1
76°
43°
2
76°
43°
3
75°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in McGill
McGill's September 2026 forecast shows daily high temperatures ranging from 65° to 87°, with overnight lows between 37° and 58°. The average high for September is 75° with an average low of 45°. 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 McGill. See also: October | November | December.