S
M
T
W
T
F
S
30
87°
75°
31
86°
77°
1
86°
77°
2
86°
77°
3
84°
77°
4
87°
74°
5
90°
75°
6
90°
75°
7
83°
76°
8
85°
77°
9
86°
75°
10
88°
75°
11
90°
74°
12
89°
73°
13
88°
72°
14
89°
74°
15
88°
73°
16
87°
73°
17
87°
74°
18
88°
73°
19
88°
74°
20
86°
73°
21
84°
74°
22
88°
74°
23
88°
73°
24
86°
74°
25
84°
74°
26
86°
73°
27
86°
74°
28
87°
74°
29
86°
73°
30
85°
73°
1
84°
72°
2
85°
73°
3
86°
72°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in St. Augustine South
St. Augustine South's September 2026 forecast shows daily high temperatures ranging from 83° to 90°, with overnight lows between 72° and 77°. The average high for September is 87° with an average low of 74°. 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. Augustine South. See also: October | November | December.