May weather in San Marcos, TX
The average temperature in San Marcos in May is 75.5°F (64.9°F–86.2°F). Average precipitation: 4.53 inches.
May is a spring month in San Marcos, and is warmer than the annual average of 68.6°F. Daily temperatures swing about 21.3°F between overnight low and afternoon high. Expect about 8 days with precipitation. Daylight averages about 13h 30m. For travel, May is a comfortable month to visit.
Avg High
86.2°F
Avg Low
64.9°F
Precipitation
4.53 in
Daylight
13h 30m
May records in San Marcos
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| May 1 | 93.9°F (1920) | 39.9°F (1908) | 1.64 in (2000) |
| May 2 | 97.0°F (1948) | 44.1°F (1903) | 2.45 in (2000) |
| May 3 | 100.0°F (1920) | 44.1°F (2013) | 2.50 in (1922) |
| May 4 | 98.1°F (1947) | 42.1°F (1970) | 4.10 in (1895) |
| May 5 | 99.0°F (1906) | 43.0°F (1945) | 2.40 in (2018) |
| May 6 | 102.0°F (1929) | 43.0°F (1945) | 4.15 in (1917) |
| May 7 | 100.0°F (1998) | 45.0°F (1917) | 1.73 in (1972) |
| May 8 | 100.0°F (1927) | 46.0°F (1908) | 2.59 in (1976) |
| May 9 | 102.9°F (1967) | 45.0°F (1984) | 2.75 in (1975) |
| May 10 | 97.0°F (1967) | 46.9°F (1984) | 5.01 in (1974) |
| May 11 | 99.0°F (1967) | 44.1°F (1981) | 5.90 in (1959) |
| May 12 | 100.9°F (1967) | 43.0°F (1960) | 4.05 in (1972) |
| May 13 | 102.0°F (2025) | 43.0°F (1960) | 3.70 in (2014) |
| May 14 | 102.0°F (2025) | 45.0°F (1971) | 3.78 in (2020) |
| May 15 | 100.0°F (1925) | 42.1°F (1907) | 7.37 in (1970) |
| May 16 | 100.9°F (1925) | 45.0°F (1942) | 6.00 in (1920) |
| May 17 | 99.0°F (1925) | 44.1°F (1945) | 2.09 in (1965) |
| May 18 | 100.0°F (1925) | 44.1°F (1945) | 2.00 in (1935) |
| May 19 | 100.0°F (1939) | 46.0°F (1967) | 1.42 in (2000) |
| May 20 | 100.0°F (1925) | 48.0°F (2002) | 1.78 in (1977) |
| May 21 | 100.9°F (1939) | 50.0°F (1960) | 3.32 in (1914) |
| May 22 | 100.9°F (1939) | 48.9°F (1947) | 1.81 in (1895) |
| May 23 | 102.9°F (1925) | 52.0°F (1967) | 1.53 in (1936) |
| May 24 | 106.0°F (1925) | 51.1°F (1945) | 4.11 in (1975) |
| May 25 | 99.0°F (1927) | 55.0°F (1910) | 2.33 in (1933) |
| May 26 | 100.9°F (1927) | 51.1°F (1947) | 2.81 in (2020) |
| May 27 | 102.9°F (1928) | 55.0°F (1930) | 3.34 in (2014) |
| May 28 | 106.0°F (1927) | 53.1°F (1934) | 3.95 in (2025) |
| May 29 | 106.0°F (1927) | 53.1°F (1947) | 5.40 in (1929) |
| May 30 | 102.0°F (1927) | 53.1°F (1947) | 3.30 in (1995) |
| May 31 | 100.9°F (1927) | 50.0°F (1984) | 3.02 in (1937) |