Weather on December 20
San Mateo, CA
55 Years of Data
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.
| 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° | — | — |
San Mateo, CA Temperature Range by Month
Average monthly highs and lows. The shaded band shows the typical daily temperature range.
San Mateo, CA Monthly Precipitation
Average rainfall per month, in inches.
San Mateo, CA Daily Temperature Calendar
Average daily high temperature for every day of the year. Each cell is the climatological mean for that calendar day across 55 years of NOAA data.
Best Time to Visit San Mateo, CA
San Mateo, CA has no months that meet our "pleasant" threshold — every season has tradeoffs.