S
M
T
W
T
F
S
30
96°
69°
31
96°
72°
1
95°
74°
2
96°
74°
3
97°
74°
4
97°
73°
5
97°
73°
6
101°
74°
7
100°
76°
8
99°
74°
9
97°
73°
10
97°
72°
11
98°
75°
12
99°
75°
13
100°
75°
14
99°
73°
15
99°
75°
16
99°
75°
17
98°
72°
18
96°
67°
19
100°
70°
20
98°
74°
21
98°
71°
22
96°
71°
23
91°
64°
24
89°
63°
25
91°
64°
26
90°
63°
27
88°
64°
28
89°
64°
29
91°
63°
30
91°
64°
1
84°
60°
2
81°
65°
3
87°
64°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Brownsville
Brownsville's September 2026 forecast shows daily high temperatures ranging from 81° to 100°, with overnight lows between 60° and 74°. The average high for September is 91° with an average low of 66°. 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 Brownsville. See also: October | November | December.
