S
M
T
W
T
F
S
30
83°
70°
31
91°
73°
1
90°
71°
2
88°
66°
3
86°
71°
4
89°
74°
5
83°
68°
6
81°
65°
7
82°
65°
8
78°
65°
9
85°
59°
10
78°
58°
11
83°
57°
12
77°
57°
13
71°
49°
14
64°
46°
15
73°
55°
16
74°
51°
17
69°
58°
18
67°
57°
19
64°
57°
20
71°
56°
21
63°
52°
22
65°
51°
23
69°
44°
24
70°
49°
25
73°
51°
26
69°
58°
27
64°
55°
28
73°
56°
29
69°
58°
30
70°
58°
1
69°
55°
2
71°
54°
3
69°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in French Island
French Island's September 2026 forecast shows daily high temperatures ranging from 64° to 73°, with overnight lows between 48° and 58°. The average high for September is 70° with an average low of 55°. 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 French Island. See also: October | November | December.