S
M
T
W
T
F
S
26
83°
71°
27
80°
70°
28
79°
67°
29
78°
70°
30
80°
71°
31
84°
72°
1
83°
71°
2
81°
69°
3
85°
70°
4
84°
64°
5
78°
66°
6
81°
65°
7
78°
63°
8
77°
64°
9
76°
62°
10
77°
64°
11
79°
70°
12
83°
71°
13
81°
64°
14
80°
62°
15
78°
63°
16
79°
69°
17
78°
63°
18
77°
63°
19
77°
64°
20
79°
62°
21
80°
67°
22
83°
69°
23
84°
69°
24
83°
70°
25
84°
69°
26
85°
68°
27
83°
67°
28
82°
69°
29
82°
67°
30
80°
61°
31
77°
58°
1
74°
59°
2
74°
59°
3
75°
60°
4
75°
59°
5
72°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Castalia
Castalia's August 2026 forecast shows daily high temperatures ranging from 72° to 85°, with overnight lows between 58° and 72°. The average high for August is 80° with an average low of 66°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Castalia. See also: September | October | November.