December weather in San Marcos, TX
The average temperature in San Marcos in December is 52.2°F (40.8°F–63.7°F). Average precipitation: 2.41 inches.
December is a winter month in San Marcos, and is cooler than the annual average of 68.6°F. Daily temperatures swing about 22.9°F between overnight low and afternoon high. Expect about 8 days with precipitation. Daylight averages about 10h 5m. For travel, December is a comfortable month to visit.
Avg High
63.7°F
Avg Low
40.8°F
Precipitation
2.41 in
Daylight
10h 5m
December records in San Marcos
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| December 1 | 84.9°F (1946) | 17.1°F (1911) | 1.93 in (1968) |
| December 2 | 86.0°F (1922) | 26.1°F (1974) | 2.02 in (1953) |
| December 3 | 84.9°F (1933) | 21.0°F (1929) | 4.38 in (1965) |
| December 4 | 89.1°F (1928) | 21.0°F (1929) | 10.00 in (1913) |
| December 5 | 86.0°F (1933) | 24.1°F (2009) | 2.04 in (1971) |
| December 6 | 86.0°F (1924) | 19.0°F (1950) | 1.44 in (1969) |
| December 7 | 84.9°F (1916) | 10.0°F (1950) | 1.80 in (1926) |
| December 8 | 84.0°F (1922) | 14.0°F (1950) | 2.00 in (1931) |
| December 9 | 82.0°F (2024) | 19.0°F (1917) | 1.02 in (2002) |
| December 10 | 84.0°F (2021) | 15.1°F (1978) | 0.72 in (1908) |
| December 11 | 91.0°F (1987) | 18.0°F (1978) | 1.05 in (1941) |
| December 12 | 84.0°F (1939) | 16.0°F (1957) | 1.38 in (1940) |
| December 13 | 87.1°F (1973) | 18.0°F (1966) | 2.20 in (1923) |
| December 14 | 88.0°F (1924) | 19.0°F (1966) | 2.25 in (1937) |
| December 15 | 86.0°F (1921) | 12.0°F (1913) | 2.68 in (1940) |
| December 16 | 87.1°F (1933) | 15.1°F (1951) | 0.77 in (2011) |
| December 17 | 86.0°F (1921) | 18.0°F (1932) | 1.25 in (2017) |
| December 18 | 86.0°F (1921) | 19.0°F (1932) | 3.63 in (1991) |
| December 19 | 80.1°F (1955) | 17.1°F (1996) | 2.27 in (2021) |
| December 20 | 84.9°F (1933) | 16.0°F (1924) | 5.98 in (1991) |
| December 21 | 86.0°F (1933) | 14.0°F (1989) | 1.98 in (1991) |
| December 22 | 84.9°F (1948) | 3.9°F (1989) | 1.98 in (1986) |
| December 23 | 86.0°F (1921) | 10.9°F (1989) | 2.50 in (1910) |
| December 24 | 84.0°F (1942) | 10.0°F (1983) | 0.80 in (1909) |
| December 25 | 89.1°F (1942) | 7.0°F (1983) | 1.70 in (1975) |
| December 26 | 89.1°F (1955) | 12.0°F (1983) | 0.92 in (1944) |
| December 27 | 82.9°F (1950) | 19.9°F (1924) | 2.75 in (1934) |
| December 28 | 82.9°F (1921) | 19.0°F (1925) | 2.18 in (1927) |
| December 29 | 82.9°F (1996) | 14.0°F (1983) | 4.10 in (1908) |
| December 30 | 86.0°F (2024) | 10.9°F (1983) | 1.48 in (1952) |
| December 31 | 84.0°F (1951) | 10.9°F (1983) | 2.00 in (1978) |