S
M
T
W
T
F
S
30
91°
71°
31
91°
73°
1
92°
74°
2
90°
68°
3
89°
67°
4
88°
68°
5
88°
68°
6
89°
72°
7
91°
72°
8
94°
73°
9
92°
73°
10
94°
72°
11
94°
71°
12
90°
72°
13
92°
72°
14
94°
66°
15
89°
66°
16
88°
65°
17
87°
66°
18
88°
67°
19
88°
68°
20
89°
68°
21
86°
69°
22
85°
70°
23
86°
68°
24
86°
69°
25
85°
68°
26
84°
68°
27
86°
67°
28
86°
68°
29
84°
68°
30
83°
67°
1
83°
66°
2
85°
65°
3
88°
61°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in San Antonio
San Antonio's September 2026 forecast shows daily high temperatures ranging from 83° to 94°, with overnight lows between 61° and 74°. The average high for September is 88° with an average low of 69°. 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 San Antonio. See also: October | November | December.
