S
M
T
W
T
F
S
30
94°
66°
31
96°
69°
1
97°
71°
2
98°
69°
3
99°
72°
4
100°
72°
5
101°
71°
6
101°
73°
7
93°
69°
8
97°
69°
9
98°
77°
10
99°
74°
11
91°
69°
12
92°
67°
13
96°
69°
14
95°
70°
15
97°
71°
16
96°
70°
17
97°
69°
18
98°
68°
19
99°
68°
20
99°
71°
21
98°
67°
22
84°
62°
23
81°
57°
24
79°
57°
25
83°
61°
26
81°
60°
27
83°
61°
28
85°
60°
29
85°
62°
30
82°
61°
1
80°
60°
2
79°
56°
3
81°
62°
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 79° to 99°, with overnight lows between 56° and 71°. The average high for September is 84° with an average low of 61°. 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.
