S
M
T
W
T
F
S
26
89°
70°
27
89°
75°
28
93°
77°
29
84°
64°
30
76°
61°
1
65°
54°
2
75°
50°
3
80°
50°
4
84°
69°
5
89°
73°
6
88°
60°
7
71°
60°
8
81°
64°
9
87°
69°
10
91°
65°
11
83°
62°
12
88°
67°
13
92°
70°
14
88°
67°
15
88°
68°
16
89°
69°
17
86°
67°
18
81°
68°
19
83°
67°
20
85°
69°
21
88°
67°
22
83°
63°
23
82°
63°
24
83°
66°
25
86°
64°
26
83°
63°
27
83°
64°
28
84°
66°
29
83°
69°
30
85°
69°
31
84°
70°
1
86°
70°
2
87°
71°
3
87°
73°
4
88°
73°
5
87°
71°
6
87°
72°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in San Marcos
San Marcos's May 2026 forecast shows daily high temperatures ranging from 71° to 92°, with overnight lows between 60° and 73°. The average high for May is 85° with an average low of 67°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in San Marcos. See also: June | July | August.
