S
M
T
W
T
F
S
26
89°
69°
27
88°
68°
28
89°
68°
29
89°
69°
30
90°
69°
31
90°
68°
1
88°
68°
2
89°
69°
3
89°
69°
4
88°
68°
5
88°
69°
6
87°
69°
7
89°
68°
8
89°
69°
9
90°
69°
10
90°
68°
11
89°
65°
12
85°
62°
13
84°
62°
14
85°
64°
15
88°
67°
16
88°
68°
17
88°
63°
18
87°
62°
19
86°
67°
20
87°
68°
21
90°
68°
22
89°
67°
23
89°
65°
24
88°
63°
25
86°
62°
26
86°
62°
27
85°
63°
28
86°
61°
29
85°
62°
30
85°
61°
31
86°
61°
1
85°
60°
2
84°
60°
3
84°
61°
4
85°
61°
5
84°
62°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in San Marcos
San Marcos's August 2026 forecast shows daily high temperatures ranging from 84° to 90°, with overnight lows between 60° and 69°. The average high for August is 87° with an average low of 65°. 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 San Marcos. See also: September | October | November.
