S
M
T
W
T
F
S
30
94°
71°
31
95°
70°
1
93°
71°
2
90°
72°
3
93°
72°
4
95°
71°
5
95°
70°
6
94°
71°
7
95°
71°
8
94°
70°
9
92°
72°
10
89°
71°
11
88°
72°
12
89°
73°
13
91°
72°
14
91°
72°
15
90°
71°
16
92°
72°
17
92°
71°
18
93°
70°
19
92°
69°
20
90°
70°
21
91°
71°
22
90°
70°
23
91°
70°
24
89°
69°
25
86°
70°
26
87°
69°
27
87°
69°
28
89°
66°
29
84°
65°
30
85°
62°
1
86°
60°
2
82°
59°
3
81°
60°
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 81° to 95°, with overnight lows between 59° and 73°. The average high for September is 90° 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.
