December weather in Half Moon Bay, CA
The average temperature in Half Moon Bay in December is 50.9°F (42.9°F–59.0°F). Average precipitation: 5.17 inches.
December is a winter month in Half Moon Bay, and is cooler than the annual average of 54.9°F. Daily temperatures swing about 16.1°F between overnight low and afternoon high. Expect about 13 days with precipitation. Daylight averages about 9h 26m. For travel, December is a wet month.
Avg High
59.0°F
Avg Low
42.9°F
Precipitation
5.17 in
Daylight
9h 26m
December records in Half Moon Bay
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| December 1 | 75.0°F (2002) | 27.0°F (1991) | 2.27 in (1952) |
| December 2 | 75.0°F (1959) | 32.0°F (2004) | 1.83 in (1961) |
| December 3 | 75.0°F (1958) | 18.0°F (1983) | 1.35 in (1980) |
| December 4 | 79.0°F (1958) | 27.0°F (2013) | 2.23 in (1952) |
| December 5 | 72.0°F (1958) | 28.0°F (2013) | 1.77 in (1952) |
| December 6 | 69.1°F (1962) | 30.9°F (2009) | 1.80 in (1955) |
| December 7 | 72.0°F (2020) | 32.0°F (1956) | 1.77 in (2004) |
| December 8 | 72.0°F (2020) | 28.0°F (2009) | 1.26 in (2004) |
| December 9 | 70.0°F (2020) | 27.0°F (1972) | 1.10 in (1955) |
| December 10 | 70.0°F (2017) | 28.9°F (1972) | 1.75 in (1996) |
| December 11 | 73.0°F (1958) | 28.9°F (1972) | 2.11 in (2014) |
| December 12 | 73.0°F (1958) | 30.9°F (2007) | 2.52 in (1995) |
| December 13 | 75.0°F (1958) | 30.9°F (2007) | 5.38 in (2021) |
| December 14 | 70.0°F (2017) | 30.0°F (2007) | 1.48 in (1997) |
| December 15 | 73.0°F (1980) | 34.0°F (1965) | 2.04 in (1968) |
| December 16 | 72.0°F (1980) | 33.1°F (2005) | 5.50 in (2002) |
| December 17 | 72.0°F (1998) | 30.9°F (2016) | 1.10 in (1977) |
| December 18 | 68.0°F (1958) | 28.9°F (2006) | 1.86 in (2005) |
| December 19 | 72.0°F (1999) | 28.9°F (2006) | 1.74 in (2010) |
| December 20 | 71.1°F (1999) | 25.0°F (1990) | 2.10 in (1981) |
| December 21 | 72.0°F (1999) | 24.1°F (1990) | 1.93 in (1996) |
| December 22 | 71.1°F (1999) | 24.1°F (1990) | 2.06 in (1982) |
| December 23 | 69.1°F (2014) | 19.0°F (1990) | 2.80 in (1955) |
| December 24 | 71.1°F (2013) | 28.0°F (1990) | 1.32 in (1959) |
| December 25 | 73.9°F (1967) | 28.9°F (1988) | 2.66 in (1983) |
| December 26 | 73.9°F (1967) | 30.9°F (2016) | 1.94 in (1948) |
| December 27 | 72.0°F (1967) | 28.9°F (2007) | 2.90 in (2004) |
| December 28 | 70.0°F (1999) | 28.0°F (2006) | 1.91 in (1991) |
| December 29 | 71.1°F (1956) | 30.0°F (2015) | 2.15 in (1981) |
| December 30 | 69.1°F (2013) | 32.0°F (1959) | 2.41 in (1976) |
| December 31 | 70.0°F (1963) | 30.9°F (1951) | 3.09 in (2022) |