S
M
T
W
T
F
S
30
69°
54°
31
72°
55°
1
72°
55°
2
71°
54°
3
72°
54°
4
71°
53°
5
71°
54°
6
68°
53°
7
64°
50°
8
66°
50°
9
71°
53°
10
72°
54°
11
63°
48°
12
67°
53°
13
71°
55°
14
73°
53°
15
70°
53°
16
71°
54°
17
71°
53°
18
70°
52°
19
69°
46°
20
67°
47°
21
67°
50°
22
68°
45°
23
62°
42°
24
62°
42°
25
61°
44°
26
64°
46°
27
66°
49°
28
67°
48°
29
67°
49°
30
66°
46°
1
64°
48°
2
64°
48°
3
65°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in James Bay
James Bay's September 2026 forecast shows daily high temperatures ranging from 61° to 73°, with overnight lows between 42° and 55°. The average high for September is 68° with an average low of 50°. 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 James Bay. See also: October | November | December.
