Weather on December 18
San Mateo, CA
55 Years of Data
About This Date
December 18th in San Mateo, CA typically brings cool winter weather, with average highs around 57°F and lows near 44°F. Over 55 years of records, the warmest December 18th was in 2023 (59°F average), while the coldest was 1992 (43°F) — a 16°F range across recorded history. Rain or other precipitation has occurred on about 33% of December 18th dates historically, with the wettest December 18th recording 4.5" 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 18th in San Mateo, CA? Bring layers as temperatures can vary throughout the day. Consider bringing rain gear or an umbrella.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 56° | 48° | 52° | — | — |
| 2024 | 57° | 46° | 52° | — | — |
| 2023warmest | 64° | 53° | 59° | 2.03" | — |
| 2022 | 56° | 38° | 47° | — | — |
| 2021 | 52° | 41° | 46° | — | — |
| 2020 | 63° | 42° | 52° | — | — |
| 2019 | 59° | 49° | 54° | 0.89" | — |
| 2018 | 59° | 47° | 53° | — | — |
| 2017 | 61° | 44° | 52° | — | — |
| 2016 | 53° | 37° | 45° | — | — |
| 2015 | 59° | 45° | 52° | 0.56" | — |
| 2014 | 60° | 52° | 56° | 0.05" | — |
| 2013 | 57° | 44° | 51° | — | — |
| 2012 | 53° | 44° | 49° | — | — |
| 2011 | 53° | 40° | 46° | — | — |
| 2010 | 61° | 55° | 58° | 0.86" | — |
| 2009 | 61° | 48° | 54° | — | — |
| 2008 | 53° | 41° | 47° | 0.08" | — |
| 2007 | 57° | 48° | 53° | 1.98" | — |
| 2006 | 55° | 35° | 45° | — | — |
| 2005 | 63° | 50° | 56° | 4.5" | — |
| 2004 | 62° | 43° | 52° | — | — |
| 2003 | 58° | 45° | 51° | — | — |
| 2002 | 55° | 42° | 49° | 0.08" | — |
| 2001 | 56° | 42° | 49° | — | — |
| 2000 | 58° | 45° | 51° | — | — |
| 1999 | 59° | 44° | 52° | — | — |
| 1998 | 59° | 45° | 52° | — | — |
| 1997 | 59° | 50° | 55° | — | — |
| 1996 | 58° | 46° | 52° | — | — |
| 1995 | 50° | 46° | 48° | 0.36" | — |
| 1994 | 57° | 45° | 51° | 0.08" | — |
| 1993 | 55° | 41° | 48° | — | — |
| 1992coldest | 50° | 35° | 43° | — | — |
| 1991 | 61° | 48° | 54° | 0.1" | — |
| 1990 | 56° | 40° | 48° | 0.2" | — |
| 1989 | 55° | 42° | 49° | — | — |
| 1988 | 55° | 42° | 49° | — | — |
| 1987 | 54° | 40° | 47° | — | — |
| 1986 | 58° | 46° | 52° | 0.86" | — |
| 1985 | 54° | 41° | 47° | — | — |
| 1984 | 53° | 42° | 48° | — | — |
| 1983 | 56° | 51° | 53° | — | — |
| 1982 | 55° | 42° | 49° | — | — |
| 1981 | 57° | 51° | 54° | 0.51" | — |
| 1980 | 57° | 45° | 51° | — | — |
| 1979 | 57° | 39° | 48° | — | — |
| 1978 | 50° | 42° | 46° | 0.43" | — |
| 1977 | 55° | 41° | 48° | 0.08" | — |
| 1976 | 61° | 34° | 47° | — | — |
| 1975 | 61° | 34° | 47° | — | — |
| 1974 | 61° | 38° | 49° | — | — |
| 1973 | 63° | 41° | 52° | — | — |
| 1972 | 60° | 48° | 54° | 0.25" | — |
| 1971 | 56° | 33° | 44° | — | — |