S
M
T
W
T
F
S
30
82°
69°
31
78°
71°
1
80°
68°
2
74°
67°
3
88°
69°
4
86°
75°
5
80°
70°
6
77°
66°
7
79°
66°
8
80°
67°
9
84°
71°
10
87°
72°
11
82°
66°
12
79°
71°
13
82°
70°
14
78°
59°
15
74°
65°
16
77°
69°
17
82°
67°
18
81°
67°
19
74°
62°
20
73°
62°
21
71°
63°
22
72°
62°
23
73°
62°
24
76°
61°
25
68°
57°
26
68°
58°
27
72°
65°
28
77°
61°
29
70°
57°
30
71°
63°
1
72°
61°
2
68°
58°
3
71°
63°
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 68° to 82°, with overnight lows between 57° and 71°. The average high for September is 74° with an average low of 63°. 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.
