Weather on December 31
San Marcos, CA
55 Years of Data
Avg High
66°F
Avg Low
43°F
Warmest
1997
65°F avg
Coldest
2010
44°F avg
About This Date
December 31st in San Marcos, CA typically brings mild winter weather, with average highs around 66°F and lows near 43°F. Over 55 years of records, the warmest December 31st was in 1997 (65°F average), while the coldest was 2010 (44°F) — a 21°F range across recorded history. Rain or other precipitation has occurred on about 29% of December 31st dates historically, with the wettest December 31st recording 2.62" of rain. The last decade has been 1.0°F warmer on this date compared to 20-30 years ago.
The last decade has been 1.0°F warmer on this date compared to 20-30 years ago.
Planning for December 31st in San Marcos, CA? Great weather for outdoor activities.
Warming Trend
0.5°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 73° | 58° | 65° | 0.71" | — |
| 2024 | 64° | 45° | 54° | 0.03" | — |
| 2023 | 62° | 50° | 56° | 0.03" | — |
| 2022 | 62° | 54° | 58° | 0.05" | — |
| 2021 | 63° | 50° | 56° | 0.08" | — |
| 2020 | 64° | 43° | 53° | — | — |
| 2019 | 70° | 49° | 59° | — | — |
| 2018 | 59° | 52° | 55° | 0.2" | — |
| 2017 | 71° | 45° | 58° | — | — |
| 2016 | 56° | 53° | 54° | 0.74" | — |
| 2015 | 66° | 36° | 51° | — | — |
| 2014 | 50° | 38° | 44° | 1.68" | — |
| 2013 | 73° | 38° | 55° | — | — |
| 2012 | 59° | 33° | 46° | — | — |
| 2011 | 77° | 44° | 61° | — | — |
| 2010coldest | 56° | 33° | 44° | — | — |
| 2009 | 70° | 48° | 59° | 0.03" | — |
| 2008 | 61° | 42° | 51° | 0.03" | — |
| 2007 | 66° | 43° | 54° | — | — |
| 2006 | 71° | 34° | 52° | — | — |
| 2005 | 61° | 48° | 54° | 0.64" | — |
| 2004 | 58° | 44° | 51° | 0.81" | — |
| 2003 | 66° | 33° | 50° | — | — |
| 2002 | 62° | 42° | 52° | — | — |
| 2001 | 61° | 55° | 58° | 0.13" | — |
| 2000 | 77° | 38° | 57° | — | — |
| 1999 | 62° | 47° | 54° | — | — |
| 1998 | 74° | 41° | 57° | — | — |
| 1997warmest | 79° | 52° | 65° | — | — |
| 1996 | 66° | 54° | 60° | — | — |
| 1995 | 70° | 46° | 58° | — | — |
| 1994 | 64° | 40° | 52° | — | — |
| 1993 | 73° | 40° | 56° | — | — |
| 1992 | 62° | 37° | 50° | — | — |
| 1991 | 67° | 44° | 55° | — | — |
| 1990 | 73° | 33° | 53° | — | — |
| 1989 | 77° | 38° | 57° | — | — |
| 1988 | 57° | 34° | 45° | — | — |
| 1987 | 65° | 35° | 50° | — | — |
| 1986 | 69° | 40° | 54° | — | — |
| 1985 | 68° | 48° | 58° | — | — |
| 1984 | 64° | 38° | 51° | — | — |
| 1983 | 73° | 47° | 60° | — | — |
| 1982 | 61° | 29° | 45° | — | — |
| 1981 | 58° | 51° | 54° | 0.23" | — |
| 1980 | 81° | 45° | 63° | — | — |
| 1979 | 71° | 47° | 59° | — | — |
| 1978 | 64° | 34° | 49° | — | — |
| 1977 | 61° | 50° | 55° | 0.05" | — |
| 1976 | 58° | 52° | 55° | 2.62" | — |
| 1975 | 59° | 46° | 53° | — | — |
| 1974 | 61° | 38° | 49° | — | — |
| 1973 | 64° | 39° | 52° | — | — |
| 1972 | 67° | 28° | 47° | — | — |
| 1971 | 65° | 36° | 50° | — | — |
55 years of data from ESCONDIDO #2