S
M
T
W
T
F
S
30
100°
82°
31
100°
84°
1
100°
82°
2
101°
81°
3
93°
82°
4
100°
78°
5
99°
80°
6
99°
81°
7
100°
82°
8
100°
84°
9
100°
83°
10
99°
80°
11
99°
82°
12
100°
78°
13
99°
82°
14
101°
81°
15
100°
81°
16
98°
82°
17
99°
83°
18
97°
82°
19
95°
79°
20
95°
79°
21
99°
79°
22
98°
75°
23
99°
78°
24
93°
77°
25
93°
72°
26
N/A
27
93°
76°
28
93°
77°
29
95°
77°
30
90°
78°
1
80°
72°
2
76°
67°
3
74°
68°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Richardson
Richardson's September 2026 forecast shows daily high temperatures ranging from 74° to 80°, with overnight lows between 67° and 72°. The average high for September is 77° 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 Richardson. See also: October | November | December.
