S
M
T
W
T
F
S
30
77°
68°
31
84°
72°
1
88°
73°
2
93°
73°
3
91°
70°
4
79°
70°
5
77°
66°
6
77°
63°
7
77°
63°
8
84°
61°
9
86°
70°
10
79°
68°
11
77°
63°
12
79°
64°
13
81°
63°
14
70°
55°
15
86°
57°
16
79°
72°
17
74°
66°
18
73°
61°
19
71°
66°
20
70°
60°
21
70°
60°
22
68°
64°
23
70°
62°
24
71°
61°
25
68°
57°
26
71°
61°
27
70°
62°
28
73°
62°
29
71°
58°
30
70°
54°
1
73°
60°
2
68°
59°
3
66°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Castalia
Castalia's September 2026 forecast shows daily high temperatures ranging from 66° to 74°, with overnight lows between 54° and 66°. The average high for September is 70° 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 Castalia. See also: October | November | December.
