S
M
T
W
T
F
S
30
86°
74°
31
86°
75°
1
87°
76°
2
88°
75°
3
86°
75°
4
85°
74°
5
85°
75°
6
86°
75°
7
85°
74°
8
85°
74°
9
86°
75°
10
86°
74°
11
89°
73°
12
90°
70°
13
86°
72°
14
87°
73°
15
88°
72°
16
87°
73°
17
89°
73°
18
89°
72°
19
88°
72°
20
88°
73°
21
87°
70°
22
84°
71°
23
84°
71°
24
85°
73°
25
84°
73°
26
86°
72°
27
85°
69°
28
87°
69°
29
85°
70°
30
87°
72°
1
86°
71°
2
85°
70°
3
84°
68°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in St. Augustine
St. Augustine's September 2026 forecast shows daily high temperatures ranging from 84° to 90°, with overnight lows between 68° and 76°. The average high for September is 86° with an average low of 73°. 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. See also: October | November | December.