S
M
T
W
T
F
S
30
83°
61°
31
75°
56°
1
74°
56°
2
76°
59°
3
79°
62°
4
82°
63°
5
82°
62°
6
81°
63°
7
81°
55°
8
80°
62°
9
80°
60°
10
82°
50°
11
77°
54°
12
75°
61°
13
78°
52°
14
80°
47°
15
73°
46°
16
67°
47°
17
69°
49°
18
70°
56°
19
72°
57°
20
76°
56°
21
75°
56°
22
78°
57°
23
78°
56°
24
79°
55°
25
79°
57°
26
78°
54°
27
76°
45°
28
74°
42°
29
64°
44°
30
63°
43°
1
64°
46°
2
65°
43°
3
66°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in St. Johns
St. Johns's September 2026 forecast shows daily high temperatures ranging from 63° to 83°, with overnight lows between 42° and 63°. The average high for September is 75° with an average low of 54°. 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. Johns. See also: October | November | December.
