December weather in Portola Valley, CA
The average temperature in Portola Valley in December is 47.0°F (40.1°F–53.8°F). Average precipitation: 8.41 inches.
December is a winter month in Portola Valley, and is cooler than the annual average of 57.1°F. Daily temperatures swing about 13.7°F between overnight low and afternoon high. Expect about 15 days with precipitation. Daylight averages about 9h 26m. For travel, December is a wet month.
Avg High
53.8°F
Avg Low
40.1°F
Precipitation
8.41 in
Daylight
9h 26m
December records in Portola Valley
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| December 1 | 79.0°F (2021) | 30.9°F (2018) | 1.95 in (1998) |
| December 2 | 72.0°F (2021) | 28.9°F (2022) | 4.10 in (2012) |
| December 3 | 66.9°F (2021) | 34.0°F (2005) | 2.93 in (2014) |
| December 4 | 68.0°F (2024) | 28.0°F (2013) | 0.61 in (1995) |
| December 5 | 72.0°F (2023) | 26.1°F (2013) | 2.60 in (1996) |
| December 6 | 68.0°F (2006) | 30.0°F (2013) | 1.14 in (2010) |
| December 7 | 70.0°F (2006) | 24.1°F (2013) | 2.30 in (2019) |
| December 8 | 71.1°F (2006) | 24.1°F (2013) | 1.70 in (2004) |
| December 9 | 71.1°F (2006) | 25.0°F (2013) | 1.30 in (2006) |
| December 10 | 71.1°F (2006) | 26.1°F (2009) | 3.60 in (2022) |
| December 11 | 68.0°F (2025) | 34.0°F (1999) | 5.67 in (2014) |
| December 12 | 77.0°F (2025) | 30.9°F (2022) | 4.46 in (1995) |
| December 13 | 71.1°F (2025) | 30.9°F (2022) | 4.76 in (2021) |
| December 14 | 71.1°F (2025) | 30.9°F (2012) | 4.00 in (2002) |
| December 15 | 69.1°F (2025) | 30.9°F (2008) | 2.41 in (2016) |
| December 16 | 71.1°F (2013) | 26.1°F (2008) | 3.90 in (2002) |
| December 17 | 75.0°F (2013) | 28.9°F (2016) | 0.78 in (2012) |
| December 18 | 73.0°F (1998) | 28.9°F (2016) | 2.90 in (2005) |
| December 19 | 70.0°F (2024) | 27.0°F (2012) | 3.00 in (2005) |
| December 20 | 66.9°F (2000) | 30.0°F (2008) | 1.98 in (2002) |
| December 21 | 64.0°F (2020) | 18.0°F (1998) | 3.56 in (2015) |
| December 22 | 62.1°F (2023) | 19.0°F (1998) | 2.84 in (2015) |
| December 23 | 66.0°F (2013) | 26.1°F (1998) | 4.18 in (2012) |
| December 24 | 64.0°F (2005) | 28.0°F (1998) | 1.33 in (2018) |
| December 25 | 68.0°F (2013) | 30.9°F (2016) | 0.98 in (2021) |
| December 26 | 71.1°F (2013) | 28.9°F (2016) | 1.61 in (2005) |
| December 27 | 71.1°F (2013) | 28.9°F (2015) | 3.08 in (2022) |
| December 28 | 66.0°F (2000) | 32.0°F (2003) | 1.96 in (2004) |
| December 29 | 73.9°F (2017) | 32.0°F (2015) | 2.72 in (2010) |
| December 30 | 73.0°F (2017) | 30.0°F (2010) | 2.98 in (2022) |
| December 31 | 68.0°F (1997) | 28.9°F (2014) | 4.54 in (2022) |