Weather on December 21
San Marcos, CA
55 Years of Data
Avg High
67°F
Avg Low
43°F
Warmest
1997
69°F avg
Coldest
1978
46°F avg
About This Date
December 21st in San Marcos, CA typically brings mild winter weather, with average highs around 67°F and lows near 43°F. Over 55 years of records, the warmest December 21st was in 1997 (69°F average), while the coldest was 1978 (46°F) — a 23°F range across recorded history. Rain or other precipitation has occurred on about 24% of December 21st dates historically, with the wettest December 21st recording 5.18" of rain. The last decade has been 2.9°F warmer on this date compared to 20-30 years ago.
The last decade has been 2.9°F warmer on this date compared to 20-30 years ago.
Planning for December 21st in San Marcos, CA? Great weather for outdoor activities.
Warming Trend
1.1°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 78° | 52° | 65° | — | — |
| 2024 | 72° | 42° | 57° | — | — |
| 2023 | 71° | 53° | 62° | 0.15" | — |
| 2022 | 75° | 40° | 57° | — | — |
| 2021 | 69° | 50° | 60° | — | — |
| 2020 | 84° | 45° | 64° | — | — |
| 2019 | 74° | 44° | 59° | — | — |
| 2018 | 67° | 50° | 58° | — | — |
| 2017 | 64° | 40° | 52° | — | — |
| 2016 | 71° | 56° | 63° | 0.1" | — |
| 2015 | 62° | 40° | 51° | — | — |
| 2014 | 69° | 47° | 58° | — | — |
| 2013 | 61° | 42° | 51° | — | — |
| 2012 | 63° | 34° | 48° | — | — |
| 2011 | 65° | 39° | 52° | — | — |
| 2010 | 57° | 53° | 55° | 5.18" | — |
| 2009 | 65° | 51° | 58° | — | — |
| 2008 | 61° | 43° | 52° | 0.03" | — |
| 2007 | 62° | 46° | 54° | 0.18" | — |
| 2006 | 57° | 56° | 56° | — | — |
| 2005 | 84° | 52° | 68° | — | — |
| 2004 | 68° | 53° | 61° | — | — |
| 2003 | 67° | 51° | 59° | — | — |
| 2002 | 54° | 44° | 49° | 0.64" | — |
| 2001 | 57° | 45° | 51° | — | — |
| 2000 | 73° | 39° | 56° | — | — |
| 1999 | 76° | 40° | 58° | — | — |
| 1998 | 56° | 36° | 46° | 0.05" | — |
| 1997warmest | 79° | 60° | 69° | 0.58" | — |
| 1996 | 65° | 37° | 51° | — | — |
| 1995 | 64° | 37° | 51° | 1.27" | — |
| 1994 | 75° | 38° | 56° | — | — |
| 1993 | 66° | 41° | 54° | — | — |
| 1992 | 61° | 32° | 46° | — | — |
| 1991 | 73° | 47° | 60° | — | — |
| 1990 | 52° | 40° | 46° | 0.05" | — |
| 1989 | 69° | 39° | 54° | — | — |
| 1988 | 62° | 50° | 56° | 1.4" | — |
| 1987 | 70° | 36° | 53° | — | — |
| 1986 | 70° | 38° | 54° | — | — |
| 1985 | 76° | 40° | 58° | — | — |
| 1984 | 60° | 35° | 48° | — | — |
| 1983 | 59° | 46° | 53° | — | — |
| 1982 | 66° | 48° | 57° | — | — |
| 1981 | 63° | 50° | 56° | 0.2" | — |
| 1980 | 80° | 41° | 61° | — | — |
| 1979 | 63° | 50° | 56° | 0.23" | — |
| 1978coldest | 62° | 31° | 46° | — | — |
| 1977 | 68° | — | — | — | — |
| 1976 | 72° | 39° | 55° | — | — |
| 1975 | 65° | 40° | 52° | — | — |
| 1974 | 72° | 36° | 54° | — | — |
| 1973 | 68° | 36° | 52° | — | — |
| 1972 | 79° | 42° | 60° | — | — |
| 1971 | 61° | 36° | 48° | — | — |
55 years of data from ESCONDIDO #2