S
M
T
W
T
F
S
26
91°
67°
27
88°
68°
28
90°
68°
29
88°
68°
30
88°
68°
1
90°
68°
2
90°
67°
3
90°
69°
4
89°
69°
5
87°
68°
6
88°
68°
7
87°
68°
8
89°
70°
9
92°
69°
10
93°
70°
11
93°
70°
12
92°
70°
13
93°
71°
14
92°
69°
15
91°
69°
16
92°
70°
17
87°
71°
18
87°
72°
19
85°
72°
20
83°
71°
21
83°
72°
22
85°
72°
23
84°
71°
24
84°
72°
25
86°
72°
26
85°
71°
27
86°
72°
28
85°
72°
29
87°
71°
30
85°
71°
31
86°
72°
1
85°
72°
2
83°
71°
3
83°
72°
4
84°
72°
5
83°
71°
6
82°
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 82° to 93°, with overnight lows between 68° and 72°. The average high for May is 87° with an average low of 71°. 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.
