S
M
T
W
T
F
S
30
88°
70°
31
86°
66°
1
93°
70°
2
95°
66°
3
93°
73°
4
91°
70°
5
90°
70°
6
88°
68°
7
84°
70°
8
86°
70°
9
82°
61°
10
81°
55°
11
84°
55°
12
73°
54°
13
59°
54°
14
75°
55°
15
70°
57°
16
67°
63°
17
74°
65°
18
86°
66°
19
76°
60°
20
66°
56°
21
69°
53°
22
70°
55°
23
71°
50°
24
70°
51°
25
70°
52°
26
75°
56°
27
74°
54°
28
75°
52°
29
62°
49°
30
72°
49°
1
76°
52°
2
69°
51°
3
66°
52°
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 62° to 86°, with overnight lows between 49° and 66°. The average high for September is 72° with an average low of 55°. 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.
