S
M
T
W
T
F
S
30
65°
46°
31
66°
45°
1
60°
44°
2
58°
47°
3
60°
50°
4
64°
51°
5
65°
50°
6
66°
52°
7
65°
51°
8
65°
51°
9
64°
50°
10
65°
43°
11
63°
41°
12
56°
42°
13
56°
41°
14
55°
40°
15
55°
39°
16
56°
39°
17
54°
40°
18
55°
43°
19
55°
40°
20
54°
39°
21
53°
42°
22
54°
43°
23
53°
42°
24
54°
39°
25
51°
37°
26
50°
37°
27
50°
36°
28
51°
40°
29
55°
42°
30
57°
43°
1
58°
44°
2
58°
43°
3
57°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in St. John Island
St. John Island's September 2026 forecast shows daily high temperatures ranging from 50° to 66°, with overnight lows between 36° and 52°. The average high for September is 58° with an average low of 43°. 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 St. John Island. See also: October | November | December.
