S
M
T
W
T
F
S
30
76°
63°
31
81°
63°
1
86°
61°
2
85°
58°
3
81°
62°
4
86°
63°
5
86°
62°
6
85°
61°
7
85°
61°
8
84°
62°
9
86°
61°
10
84°
61°
11
82°
59°
12
85°
48°
13
79°
54°
14
83°
53°
15
84°
47°
16
77°
44°
17
72°
47°
18
72°
45°
19
76°
48°
20
72°
53°
21
71°
50°
22
71°
46°
23
77°
48°
24
80°
44°
25
79°
44°
26
80°
52°
27
80°
42°
28
69°
52°
29
75°
50°
30
75°
52°
1
79°
38°
2
78°
36°
3
63°
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 63° to 86°, with overnight lows between 36° and 63°. The average high for September is 79° with an average low of 52°. 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.
