S
M
T
W
T
F
S
30
101°
79°
31
102°
81°
1
100°
80°
2
100°
78°
3
94°
76°
4
100°
77°
5
100°
79°
6
100°
78°
7
102°
79°
8
102°
82°
9
101°
82°
10
101°
79°
11
100°
78°
12
102°
77°
13
101°
80°
14
101°
80°
15
101°
81°
16
100°
81°
17
99°
80°
18
98°
78°
19
96°
76°
20
96°
79°
21
98°
75°
22
96°
73°
23
98°
76°
24
94°
78°
25
92°
71°
26
95°
72°
27
96°
76°
28
93°
78°
29
95°
77°
30
90°
73°
1
79°
71°
2
77°
67°
3
76°
67°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Lewisville
Lewisville's September 2026 forecast shows daily high temperatures ranging from 76° to 90°, with overnight lows between 67° and 73°. The average high for September is 81° 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 Lewisville. See also: October | November | December.
