Weather on December 20
San Mateo, CA
55 Years of Data
Avg High
56°F
Avg Low
43°F
Warmest
1999
60°F avg
Coldest
1990
40°F avg
About This Date
December 20th in San Mateo, CA typically brings cool winter weather, with average highs around 56°F and lows near 43°F. Over 55 years of records, the warmest December 20th was in 1999 (60°F average), while the coldest was 1990 (40°F) — a 20°F range across recorded history. Rain or other precipitation has occurred on about 27% of December 20th dates historically, with the wettest December 20th recording 3.3" of rain. Temperatures on this date have remained relatively stable over the past several decades.
Temperatures on this date have remained relatively stable over the past several decades.
Planning for December 20th in San Mateo, CA? Bring layers as temperatures can vary throughout the day.
Warming Trend
0.8°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 62° | 56° | 59° | 0.08" | — |
| 2024 | 56° | 45° | 50° | — | — |
| 2023 | 60° | 55° | 58° | 3.3" | — |
| 2022 | 53° | 45° | 49° | — | — |
| 2021 | 54° | 45° | 49° | — | — |
| 2020 | 62° | 42° | 52° | — | — |
| 2019 | 56° | 47° | 51° | — | — |
| 2018 | 55° | 47° | 51° | — | — |
| 2017 | 55° | 47° | 51° | 0.1" | — |
| 2016 | 56° | 40° | 48° | — | — |
| 2015 | 54° | 42° | 48° | 0.61" | — |
| 2014 | 62° | 56° | 59° | 0.05" | — |
| 2013 | 60° | 40° | 50° | — | — |
| 2012 | 60° | 37° | 49° | — | — |
| 2011 | 60° | 40° | 50° | — | — |
| 2010 | 54° | 48° | 51° | — | — |
| 2009 | 59° | 47° | 53° | — | — |
| 2008 | 50° | 36° | 43° | — | — |
| 2007 | 54° | 49° | 51° | 1.02" | — |
| 2006 | 50° | 36° | 43° | — | — |
| 2005 | 63° | 50° | 56° | — | — |
| 2004 | 53° | 45° | 49° | — | — |
| 2003 | 57° | 51° | 54° | 0.13" | — |
| 2002 | 56° | 45° | 50° | 1.75" | — |
| 2001 | 54° | 48° | 51° | 1.47" | — |
| 2000 | 58° | 44° | 51° | — | — |
| 1999warmest | 69° | 52° | 60° | — | — |
| 1998 | 46° | 37° | 42° | 0.43" | — |
| 1997 | 58° | 41° | 49° | 0.03" | — |
| 1996 | 55° | 42° | 49° | — | — |
| 1995 | 60° | 44° | 52° | — | — |
| 1994 | 51° | 41° | 46° | — | — |
| 1993 | 50° | 40° | 45° | — | — |
| 1992 | 53° | 43° | 48° | — | — |
| 1991 | 57° | 40° | 48° | — | — |
| 1990coldest | 46° | 34° | 40° | — | — |
| 1989 | 51° | 43° | 47° | — | — |
| 1988 | 52° | 44° | 48° | 2.21" | — |
| 1987 | 54° | 39° | 46° | — | — |
| 1986 | 58° | 43° | 50° | — | — |
| 1985 | 53° | 39° | 46° | — | — |
| 1984 | 54° | 39° | 46° | — | — |
| 1983 | 55° | 42° | 49° | — | — |
| 1982 | 60° | 48° | 54° | 0.97" | — |
| 1981 | 61° | 57° | 59° | 0.3" | — |
| 1980 | 62° | 48° | 55° | — | — |
| 1979 | 56° | 47° | 51° | 0.18" | — |
| 1978 | 58° | 31° | 44° | — | — |
| 1977 | 52° | 38° | 45° | — | — |
| 1976 | 60° | 37° | 49° | — | — |
| 1975 | 60° | 35° | 48° | — | — |
| 1974 | 55° | 42° | 49° | — | — |
| 1973 | 59° | 42° | 51° | — | — |
| 1972 | 58° | 41° | 49° | — | — |
| 1971 | 55° | 35° | 45° | — | — |
55 years of data from BURLINGAME