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
N/A
9
97°
77°
10
97°
78°
11
99°
78°
12
100°
79°
13
101°
76°
14
99°
77°
15
98°
75°
16
95°
74°
17
94°
72°
18
92°
71°
19
93°
72°
20
89°
70°
21
88°
68°
22
91°
72°
23
90°
71°
24
84°
71°
25
82°
70°
26
83°
70°
27
84°
69°
28
84°
70°
29
86°
70°
30
86°
65°
1
81°
61°
2
79°
60°
3
79°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in San Antonio
San Antonio's September 2026 forecast shows daily high temperatures ranging from 79° to 101°, with overnight lows between 59° and 79°. The average high for September is 90° with an average low of 71°. 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.
