S
M
T
W
T
F
S
30
82°
63°
31
77°
64°
1
82°
63°
2
79°
59°
3
76°
55°
4
78°
59°
5
82°
61°
6
81°
61°
7
83°
62°
8
84°
62°
9
84°
61°
10
82°
62°
11
76°
60°
12
74°
51°
13
78°
54°
14
74°
50°
15
76°
49°
16
77°
46°
17
72°
49°
18
71°
48°
19
70°
45°
20
69°
45°
21
70°
46°
22
70°
46°
23
72°
47°
24
76°
52°
25
78°
55°
26
78°
54°
27
70°
48°
28
77°
53°
29
70°
44°
30
71°
53°
1
71°
41°
2
76°
40°
3
71°
39°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Walnut
Walnut's September 2026 forecast shows daily high temperatures ranging from 69° to 84°, with overnight lows between 39° and 64°. The average high for September is 76° with an average low of 53°. 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 Walnut. See also: October | November | December.
