S
M
T
W
T
F
S
30
96°
72°
31
97°
75°
1
99°
72°
2
99°
72°
3
100°
77°
4
90°
76°
5
97°
74°
6
96°
72°
7
98°
72°
8
98°
74°
9
98°
73°
10
96°
73°
11
99°
75°
12
99°
75°
13
98°
75°
14
98°
76°
15
99°
76°
16
98°
73°
17
96°
71°
18
89°
71°
19
92°
73°
20
93°
76°
21
97°
74°
22
94°
74°
23
94°
73°
24
95°
72°
25
93°
72°
26
97°
69°
27
95°
68°
28
93°
69°
29
91°
69°
30
93°
67°
1
92°
68°
2
86°
63°
3
86°
68°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in San Antonio Northwest
San Antonio Northwest's September 2026 forecast shows daily high temperatures ranging from 86° to 97°, with overnight lows between 63° and 76°. The average high for September is 93° with an average low of 70°. 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 Northwest. See also: October | November | December.
