S
M
T
W
T
F
S
30
92°
67°
31
87°
61°
1
86°
64°
2
86°
63°
3
90°
64°
4
91°
63°
5
92°
66°
6
93°
66°
7
94°
67°
8
93°
66°
9
92°
67°
10
93°
67°
11
92°
65°
12
92°
65°
13
91°
64°
14
92°
65°
15
91°
65°
16
91°
64°
17
90°
65°
18
86°
61°
19
81°
57°
20
81°
57°
21
80°
56°
22
81°
56°
23
82°
60°
24
81°
57°
25
81°
56°
26
82°
57°
27
80°
55°
28
80°
58°
29
81°
60°
30
79°
57°
1
79°
58°
2
80°
57°
3
79°
58°
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 79° to 94°, with overnight lows between 55° and 67°. The average high for September is 86° with an average low of 62°. 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.
