S
M
T
W
T
F
S
30
92°
66°
31
95°
66°
1
93°
65°
2
93°
64°
3
94°
64°
4
92°
61°
5
92°
61°
6
91°
60°
7
91°
62°
8
92°
63°
9
92°
63°
10
91°
64°
11
93°
64°
12
89°
61°
13
89°
67°
14
94°
68°
15
Hist. Avg.
91°
63°
16
Hist. Avg.
91°
63°
17
Hist. Avg.
91°
62°
18
Hist. Avg.
90°
62°
19
Hist. Avg.
90°
62°
20
Hist. Avg.
90°
62°
21
Hist. Avg.
89°
62°
22
Hist. Avg.
89°
61°
23
Hist. Avg.
88°
61°
24
Hist. Avg.
88°
61°
25
Hist. Avg.
88°
61°
26
Hist. Avg.
87°
60°
27
Hist. Avg.
87°
60°
28
Hist. Avg.
86°
60°
29
Hist. Avg.
86°
60°
30
Hist. Avg.
86°
59°
1
Hist. Avg.
85°
59°
2
Hist. Avg.
85°
59°
3
Hist. Avg.
84°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Castaic Junction
Castaic Junction's September 2026 forecast shows daily high temperatures ranging from 89° to 95°, with overnight lows between 60° and 68°. The average high for September is 92° with an average low of 64°. 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 Castaic Junction. See also: October | November | December.
