S
M
T
W
T
F
S
30
80°
51°
31
79°
54°
1
81°
52°
2
82°
53°
3
82°
54°
4
84°
54°
5
83°
53°
6
83°
53°
7
82°
55°
8
84°
53°
9
83°
51°
10
82°
52°
11
80°
50°
12
73°
50°
13
79°
49°
14
78°
49°
15
74°
48°
16
72°
46°
17
78°
48°
18
78°
49°
19
74°
49°
20
75°
45°
21
74°
46°
22
73°
43°
23
73°
47°
24
74°
47°
25
72°
46°
26
77°
48°
27
77°
43°
28
72°
45°
29
76°
44°
30
77°
38°
1
70°
35°
2
65°
38°
3
69°
39°
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 65° to 84°, with overnight lows between 35° and 55°. The average high for September is 77° with an average low of 48°. 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.
