Weather on December 31
San Mateo, CA
55 Years of Data
Avg High
55°F
Avg Low
44°F
Warmest
1996
63°F avg
Coldest
1978
42°F avg
About This Date
December 31st in San Mateo, CA typically brings cool winter weather, with average highs around 55°F and lows near 44°F. Over 55 years of records, the warmest December 31st was in 1996 (63°F average), while the coldest was 1978 (42°F) — a 21°F range across recorded history. Rain or other precipitation has occurred on about 31% of December 31st dates historically, with the wettest December 31st recording 9.32" of rain. The last decade has been 1.5°F cooler on this date compared to 20-30 years ago.
The last decade has been 1.5°F cooler on this date compared to 20-30 years ago.
Planning for December 31st in San Mateo, CA? Bring layers as temperatures can vary throughout the day. Consider bringing rain gear or an umbrella.
Warming Trend
0.6°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 52° | 48° | 50° | 2.39" | — |
| 2024 | 58° | 43° | 50° | — | — |
| 2023 | 58° | 49° | 53° | — | — |
| 2022 | 62° | 53° | 58° | 9.32" | — |
| 2021 | 54° | 41° | 47° | — | — |
| 2020 | 60° | 47° | 53° | 0.08" | — |
| 2019 | 57° | 41° | 49° | — | — |
| 2018 | 55° | 44° | 50° | — | — |
| 2017 | 57° | 45° | 51° | — | — |
| 2016 | 53° | 44° | 49° | — | — |
| 2015 | 51° | 39° | 45° | — | — |
| 2014 | 58° | 41° | 49° | — | — |
| 2013 | 59° | 41° | 50° | — | — |
| 2012 | 53° | 37° | 45° | — | — |
| 2011 | 57° | 43° | 50° | — | — |
| 2010 | 49° | 38° | 43° | — | — |
| 2009 | 56° | 49° | 52° | — | — |
| 2008 | 51° | 44° | 48° | — | — |
| 2007 | 54° | 37° | 45° | — | — |
| 2006 | 51° | 47° | 49° | — | — |
| 2005 | 61° | 51° | 56° | 4.72" | — |
| 2004 | 56° | 47° | 51° | 0.94" | — |
| 2003 | 54° | 45° | 49° | — | — |
| 2002 | 57° | 45° | 51° | 1.19" | — |
| 2001 | 60° | 54° | 57° | — | — |
| 2000 | 53° | 44° | 49° | — | — |
| 1999 | 53° | 40° | 46° | — | — |
| 1998 | 57° | 46° | 52° | 0.03" | — |
| 1997 | 56° | 47° | 51° | — | — |
| 1996warmest | 67° | 59° | 63° | 0.38" | — |
| 1995 | 60° | 51° | 56° | — | — |
| 1994 | 48° | 43° | 45° | 0.94" | — |
| 1993 | 54° | 45° | 49° | — | — |
| 1992 | 56° | 46° | 51° | 0.03" | — |
| 1991 | 57° | 45° | 51° | — | — |
| 1990 | 53° | 32° | 43° | — | — |
| 1989 | 55° | 41° | 48° | — | — |
| 1988 | 52° | 40° | 46° | 0.15" | — |
| 1987 | 49° | 37° | 43° | — | — |
| 1986 | 50° | 46° | 48° | 0.3" | — |
| 1985 | 55° | 47° | 51° | — | — |
| 1984 | 50° | 39° | 45° | — | — |
| 1983 | 60° | 49° | 54° | — | — |
| 1982 | 51° | 35° | 43° | — | — |
| 1981 | 52° | 48° | 50° | 0.18" | — |
| 1980 | 53° | 37° | 45° | — | — |
| 1979 | 63° | 53° | 58° | 0.36" | — |
| 1978coldest | 58° | 27° | 42° | — | — |
| 1977 | 56° | 42° | 49° | 0.03" | — |
| 1976 | 54° | 47° | 50° | 0.15" | — |
| 1975 | 51° | 43° | 47° | — | — |
| 1974 | 58° | 43° | 50° | — | — |
| 1973 | 55° | 40° | 47° | 0.36" | — |
| 1972 | 57° | 35° | 46° | — | — |
| 1971 | 55° | 34° | 44° | — | — |
55 years of data from BURLINGAME