S
M
T
W
T
F
S
30
100°
75°
31
100°
75°
1
100°
75°
2
99°
76°
3
91°
76°
4
98°
75°
5
99°
75°
6
99°
75°
7
100°
75°
8
103°
79°
9
99°
78°
10
98°
80°
11
96°
80°
12
101°
77°
13
100°
77°
14
98°
75°
15
96°
71°
16
92°
70°
17
90°
69°
18
91°
70°
19
89°
65°
20
85°
66°
21
86°
63°
22
91°
70°
23
90°
68°
24
88°
68°
25
81°
67°
26
86°
67°
27
85°
66°
28
88°
67°
29
85°
67°
30
84°
58°
1
77°
55°
2
76°
56°
3
74°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Allen
Allen's September 2026 forecast shows daily high temperatures ranging from 74° to 103°, with overnight lows between 54° and 80°. The average high for September is 90° with an average low of 69°. 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 Allen. See also: October | November | December.
