S
M
T
W
T
F
S
30
80°
45°
31
78°
46°
1
79°
44°
2
80°
44°
3
79°
47°
4
79°
43°
5
77°
44°
6
78°
45°
7
77°
42°
8
74°
41°
9
73°
39°
10
72°
40°
11
76°
39°
12
77°
41°
13
77°
39°
14
76°
44°
15
76°
42°
16
74°
43°
17
73°
35°
18
71°
33°
19
68°
35°
20
69°
35°
21
70°
38°
22
74°
42°
23
74°
42°
24
69°
41°
25
68°
42°
26
67°
39°
27
67°
37°
28
66°
35°
29
64°
35°
30
72°
38°
1
68°
37°
2
69°
37°
3
Hist. Avg.
68°
30°
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 64° to 80°, with overnight lows between 33° and 47°. The average high for September is 73° with an average low of 40°. 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.
