S
M
T
W
T
F
S
30
92°
76°
31
90°
67°
1
90°
64°
2
88°
63°
3
86°
65°
4
85°
64°
5
85°
70°
6
85°
69°
7
89°
70°
8
92°
69°
9
95°
69°
10
90°
66°
11
91°
62°
12
93°
65°
13
92°
66°
14
93°
66°
15
92°
65°
16
93°
65°
17
93°
64°
18
91°
58°
19
86°
58°
20
87°
59°
21
88°
60°
22
89°
60°
23
89°
59°
24
87°
55°
25
80°
52°
26
80°
52°
27
79°
51°
28
80°
52°
29
81°
53°
30
80°
52°
1
80°
53°
2
81°
57°
3
86°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Joshua Tree
Joshua Tree's September 2026 forecast shows daily high temperatures ranging from 79° to 95°, with overnight lows between 51° and 70°. The average high for September is 87° with an average low of 61°. 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 Joshua Tree. See also: October | November | December.