S
M
T
W
T
F
S
30
97°
77°
31
97°
73°
1
91°
78°
2
100°
81°
3
90°
77°
4
91°
74°
5
93°
74°
6
92°
75°
7
94°
75°
8
91°
73°
9
93°
72°
10
92°
74°
11
94°
73°
12
95°
73°
13
92°
73°
14
91°
74°
15
89°
72°
16
90°
68°
17
92°
72°
18
89°
71°
19
91°
70°
20
91°
72°
21
90°
72°
22
91°
71°
23
90°
71°
24
90°
70°
25
88°
71°
26
90°
70°
27
85°
66°
28
83°
62°
29
84°
62°
30
83°
61°
1
86°
62°
2
89°
68°
3
83°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Katy
Katy's September 2026 forecast shows daily high temperatures ranging from 83° to 95°, with overnight lows between 60° and 77°. The average high for September is 90° 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 Katy. See also: October | November | December.
