S
M
T
W
T
F
S
30
94°
66°
31
96°
70°
1
98°
71°
2
99°
71°
3
100°
73°
4
100°
74°
5
101°
72°
6
89°
70°
7
88°
65°
8
92°
71°
9
95°
76°
10
91°
72°
11
85°
70°
12
86°
70°
13
89°
71°
14
91°
71°
15
88°
69°
16
86°
70°
17
83°
66°
18
76°
58°
19
79°
62°
20
79°
61°
21
76°
60°
22
79°
62°
23
78°
57°
24
83°
63°
25
82°
61°
26
81°
61°
27
82°
60°
28
82°
61°
29
81°
61°
30
78°
60°
1
74°
59°
2
77°
58°
3
79°
59°
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 74° to 91°, with overnight lows between 57° and 72°. The average high for September is 82° 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.
