S
M
T
W
T
F
S
30
100°
76°
31
100°
77°
1
100°
79°
2
103°
76°
3
103°
81°
4
94°
79°
5
100°
78°
6
100°
78°
7
101°
76°
8
103°
78°
9
100°
78°
10
100°
76°
11
104°
77°
12
103°
79°
13
99°
78°
14
98°
79°
15
101°
77°
16
98°
76°
17
92°
76°
18
95°
71°
19
95°
72°
20
96°
73°
21
93°
70°
22
92°
70°
23
93°
71°
24
94°
73°
25
95°
71°
26
87°
65°
27
86°
70°
28
85°
70°
29
87°
69°
30
88°
70°
1
89°
70°
2
88°
69°
3
85°
69°
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 85° to 101°, with overnight lows between 65° and 79°. The average high for September is 92° with an average low of 72°. 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.
