Weather on December 21
Hayward, CA
55 Years of Data
Avg High
58°F
Avg Low
43°F
Warmest
2025
63°F avg
Coldest
1998
37°F avg
About This Date
December 21st in Hayward, CA typically brings cool winter weather, with average highs around 58°F and lows near 43°F. Over 53 years of records, the warmest December 21st was in 2025 (63°F average), while the coldest was 1998 (37°F) — a 26°F range across recorded history. Rain or other precipitation has occurred on about 38% of December 21st dates historically, with the wettest December 21st recording 2.79" 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 Hayward, CA? Bring layers as temperatures can vary throughout the day. Consider bringing rain gear or an umbrella.
Warming Trend
0.9°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025warmest | 65° | 61° | 63° | 0.03" | — |
| 2024 | 63° | 47° | 55° | 0.13" | — |
| 2023 | 63° | 50° | 56° | — | — |
| 2022 | 58° | 40° | 49° | — | — |
| 2021 | 56° | 41° | 48° | 0.43" | — |
| 2020 | 60° | 40° | 50° | — | — |
| 2019 | 61° | 45° | 53° | — | — |
| 2018 | 61° | 47° | 54° | 0.05" | — |
| 2017 | 59° | 35° | 47° | — | — |
| 2016 | 66° | 42° | 54° | — | — |
| 2015 | 57° | 51° | 54° | 1.5" | — |
| 2014 | 65° | 56° | 60° | 0.03" | — |
| 2013 | 62° | 39° | 51° | — | — |
| 2012 | 59° | 51° | 55° | 0.15" | — |
| 2011 | 63° | 37° | 50° | — | — |
| 2010 | 59° | 47° | 53° | 0.23" | — |
| 2009 | 58° | 48° | 53° | 0.23" | — |
| 2008 | 51° | 43° | 47° | 0.94" | — |
| 2007 | 55° | 35° | 45° | — | — |
| 2006 | 52° | 41° | 46° | 0.99" | — |
| 2005 | 67° | 56° | 61° | 0.36" | — |
| 2004 | 61° | 38° | 49° | — | — |
| 2003 | 60° | 48° | 54° | 0.03" | — |
| 2002 | 57° | 45° | 51° | 0.43" | — |
| 2001 | 53° | 41° | 47° | 0.03" | — |
| 2000 | 58° | 40° | 49° | — | — |
| 1999 | 73° | 44° | 59° | — | — |
| 1998coldest | 46° | 29° | 37° | — | — |
| 1997 | 53° | 37° | 45° | — | — |
| 1996 | 50° | 47° | 48° | — | — |
| 1995 | 61° | 54° | 57° | — | — |
| 1994 | 61° | 53° | 57° | — | — |
| 1993 | 46° | 31° | 38° | — | — |
| 1992 | 53° | 40° | 46° | — | — |
| 1989 | 58° | 38° | 48° | — | — |
| 1988 | 51° | 38° | 44° | 2.79" | — |
| 1987 | 59° | 38° | 48° | — | — |
| 1986 | 60° | 41° | 51° | — | — |
| 1985 | 64° | 36° | 50° | — | — |
| 1984 | 56° | 38° | 47° | — | — |
| 1983 | 52° | 38° | 45° | — | — |
| 1982 | 59° | 45° | 52° | 2.31" | — |
| 1981 | 60° | 49° | 54° | 0.71" | — |
| 1980 | 66° | 50° | 58° | — | — |
| 1979 | 57° | 50° | 54° | 0.36" | — |
| 1978 | 54° | 34° | 44° | — | — |
| 1977 | 63° | 43° | 53° | — | — |
| 1976 | 69° | 47° | 58° | — | — |
| 1975 | 55° | 36° | 45° | — | — |
| 1974 | 56° | 37° | 46° | — | — |
| 1973 | 60° | 42° | 51° | 0.48" | — |
| 1972 | 57° | 47° | 52° | — | — |
| 1971 | 51° | 37° | 44° | — | — |
53 years of data from HAYWARD AIR TERMINAL