S
M
T
W
T
F
S
30
53°
43°
31
42°
38°
1
49°
40°
2
48°
32°
3
50°
28°
4
62°
44°
5
64°
51°
6
64°
48°
7
64°
47°
8
62°
50°
9
52°
45°
10
53°
45°
11
62°
38°
12
51°
38°
13
52°
35°
14
55°
36°
15
51°
36°
16
51°
43°
17
54°
39°
18
52°
34°
19
56°
42°
20
52°
36°
21
44°
38°
22
38°
35°
23
39°
34°
24
50°
26°
25
56°
34°
26
56°
37°
27
56°
36°
28
47°
37°
29
41°
29°
30
42°
32°
1
41°
29°
2
36°
21°
3
39°
23°
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 36° to 56°, with overnight lows between 21° and 37°. The average high for September is 43° 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.
