Weather on December 20
Fullerton, CA
55 Years of Data
Avg High
70°F
Avg Low
45°F
Warmest
2016
70°F avg
Coldest
1978
47°F avg
About This Date
December 20th in Fullerton, CA typically brings pleasant winter weather, with average highs around 70°F and lows near 45°F — a 25°F daily swing. Over 55 years of records, the warmest December 20th was in 2016 (70°F average), while the coldest was 1978 (47°F) — a 23°F range across recorded history. Rain or other precipitation has occurred on about 16% of December 20th dates historically, with the wettest December 20th recording 3.43" of rain. The last decade has been 1.8°F warmer on this date compared to 20-30 years ago.
The last decade has been 1.8°F warmer on this date compared to 20-30 years ago.
Planning for December 20th in Fullerton, CA? Great weather for outdoor activities.
Warming Trend
0.7°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 68° | 53° | 61° | — | — |
| 2024 | 69° | 45° | 57° | — | — |
| 2023 | 68° | 58° | 63° | 0.15" | — |
| 2022 | 71° | 40° | 55° | — | — |
| 2021 | 71° | 43° | 57° | — | — |
| 2020 | 83° | 45° | 64° | — | — |
| 2019 | 79° | 44° | 61° | — | — |
| 2018 | 80° | 49° | 64° | — | — |
| 2017 | 68° | 45° | 56° | — | — |
| 2016warmest | 80° | 61° | 70° | 0.03" | — |
| 2015 | 63° | 43° | 53° | 0.33" | — |
| 2014 | 64° | 49° | 56° | — | — |
| 2013 | 64° | 42° | 53° | — | — |
| 2012 | 71° | 48° | 60° | — | — |
| 2011 | 70° | 44° | 57° | — | — |
| 2010 | 60° | 43° | 51° | 3.43" | — |
| 2009 | 72° | 55° | 63° | — | — |
| 2008 | 63° | 41° | 52° | — | — |
| 2007 | 62° | 51° | 57° | — | — |
| 2006 | 63° | 40° | 51° | — | — |
| 2005 | 82° | 54° | 68° | — | — |
| 2004 | 80° | 49° | 64° | — | — |
| 2003 | 67° | 50° | 58° | — | — |
| 2002 | 58° | 47° | 52° | 2.11" | — |
| 2001 | 66° | 44° | 55° | — | — |
| 2000 | 78° | 43° | 60° | — | — |
| 1999 | 80° | 49° | 64° | — | — |
| 1998 | 57° | 47° | 52° | 0.48" | — |
| 1997 | 67° | 46° | 56° | — | — |
| 1996 | 75° | 46° | 61° | — | — |
| 1995 | 65° | 48° | 56° | — | — |
| 1994 | 76° | 44° | 60° | — | — |
| 1993 | 66° | 49° | 57° | — | — |
| 1992 | 66° | 38° | 52° | — | — |
| 1991 | 71° | 53° | 62° | — | — |
| 1990 | 56° | 40° | 48° | — | — |
| 1989 | 69° | 44° | 57° | — | — |
| 1988 | 63° | 41° | 52° | — | — |
| 1987 | 68° | 43° | 55° | — | — |
| 1986 | 66° | 46° | 56° | 0.18" | — |
| 1985 | 79° | 47° | 63° | — | — |
| 1984 | 61° | 44° | 52° | 0.51" | — |
| 1983 | 64° | 50° | 57° | — | — |
| 1982 | 69° | 42° | 56° | — | — |
| 1981 | 68° | 41° | 55° | — | — |
| 1980 | 76° | 44° | 60° | — | — |
| 1979 | 69° | 35° | 52° | — | — |
| 1978coldest | 64° | 30° | 47° | — | — |
| 1977 | 71° | 48° | 60° | — | — |
| 1976 | 70° | 43° | 56° | — | — |
| 1975 | 71° | 38° | 54° | 0.03" | — |
| 1974 | 73° | 42° | 58° | — | — |
| 1973 | 77° | 50° | 64° | — | — |
| 1972 | 84° | 44° | 64° | — | — |
| 1971 | 65° | 36° | 50° | — | — |
55 years of data from ANAHEIM