S
M
T
W
T
F
S
30
62°
39°
31
63°
38°
1
62°
38°
2
60°
40°
3
61°
38°
4
60°
35°
5
59°
37°
6
55°
38°
7
52°
39°
8
54°
38°
9
53°
38°
10
49°
30°
11
49°
28°
12
48°
28°
13
53°
32°
14
53°
30°
15
54°
32°
16
54°
31°
17
53°
36°
18
54°
36°
19
49°
35°
20
45°
35°
21
46°
24°
22
42°
29°
23
42°
29°
24
43°
21°
25
42°
17°
26
39°
18°
27
36°
25°
28
38°
23°
29
38°
19°
30
39°
18°
1
35°
18°
2
34°
20°
3
36°
18°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Richardson
Richardson's September 2026 forecast shows daily high temperatures ranging from 34° to 63°, with overnight lows between 17° and 40°. The average high for September is 49° with an average low of 30°. 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 Richardson. See also: October | November | December.
