S
M
T
W
T
F
S
30
101°
79°
31
102°
81°
1
100°
80°
2
100°
78°
3
93°
78°
4
96°
78°
5
99°
77°
6
100°
80°
7
101°
78°
8
98°
77°
9
96°
76°
10
99°
76°
11
102°
78°
12
100°
76°
13
95°
75°
14
93°
73°
15
91°
71°
16
88°
67°
17
92°
72°
18
83°
67°
19
86°
71°
20
90°
71°
21
91°
70°
22
90°
69°
23
90°
70°
24
91°
70°
25
90°
68°
26
89°
64°
27
80°
58°
28
80°
58°
29
79°
59°
30
84°
63°
1
88°
66°
2
88°
59°
3
78°
56°
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 78° to 102°, with overnight lows between 56° and 80°. The average high for September is 91° 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.
