Weather on December 18
Sunnyvale, CA
55 Years of Data
Avg High
59°F
Avg Low
42°F
Warmest
2010
59°F avg
Coldest
2016
42°F avg
About This Date
December 18th in Sunnyvale, CA typically brings cool winter weather, with average highs around 59°F and lows near 42°F. Over 55 years of records, the warmest December 18th was in 2010 (59°F average), while the coldest was 2016 (42°F) — a 17°F range across recorded history. Rain or other precipitation has occurred on about 31% of December 18th dates historically, with the wettest December 18th recording 3.4" of rain. The last decade has been 1.0°F cooler on this date compared to 20-30 years ago.
The last decade has been 1.0°F cooler on this date compared to 20-30 years ago.
Planning for December 18th in Sunnyvale, CA? Bring layers as temperatures can vary throughout the day. Consider bringing rain gear or an umbrella.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 59° | 45° | 52° | — | — |
| 2024 | 60° | 46° | 53° | — | — |
| 2023 | 65° | 52° | 58° | 1.22" | — |
| 2022 | 58° | 34° | 46° | — | — |
| 2021 | 54° | 33° | 43° | — | — |
| 2020 | 62° | 37° | 50° | — | — |
| 2019 | 58° | 50° | 54° | 0.25" | — |
| 2018 | 63° | 43° | 53° | — | — |
| 2017 | 63° | 38° | 50° | — | — |
| 2016coldest | 52° | 32° | 42° | — | — |
| 2015 | 61° | 40° | 50° | 0.23" | — |
| 2014 | 63° | 52° | 57° | — | — |
| 2013 | 58° | 43° | 50° | — | — |
| 2012 | 53° | 39° | 46° | — | — |
| 2011 | 58° | 39° | 48° | — | — |
| 2010warmest | 63° | 55° | 59° | 0.3" | — |
| 2009 | 63° | 46° | 54° | — | — |
| 2008 | 55° | 32° | 44° | 0.05" | — |
| 2007 | 58° | 42° | 50° | 0.94" | — |
| 2006 | 55° | 32° | 44° | — | — |
| 2005 | 62° | 52° | 57° | 3.4" | — |
| 2004 | 63° | 38° | 50° | 0.03" | — |
| 2003 | 62° | 40° | 51° | — | — |
| 2002 | 57° | 41° | 49° | 0.08" | — |
| 2001 | 56° | 43° | 49° | — | — |
| 2000 | 60° | 43° | 51° | — | — |
| 1999 | 57° | 40° | 48° | — | — |
| 1998 | 63° | 40° | 51° | — | — |
| 1997 | 59° | 49° | 54° | — | — |
| 1996 | 62° | 40° | 51° | — | — |
| 1995 | 56° | 38° | 47° | 0.66" | — |
| 1994 | 59° | 45° | 52° | — | — |
| 1993 | 57° | 39° | 48° | — | — |
| 1992 | 53° | 35° | 44° | — | — |
| 1991 | 64° | 48° | 56° | 0.13" | — |
| 1990 | 59° | 39° | 49° | 0.08" | — |
| 1989 | 58° | 44° | 51° | — | — |
| 1988 | 56° | 40° | 48° | — | — |
| 1987 | 58° | 39° | 48° | — | — |
| 1986 | 58° | 47° | 52° | 0.36" | — |
| 1985 | 63° | 39° | 51° | — | — |
| 1984 | 55° | 42° | 49° | — | — |
| 1983 | 56° | 49° | 52° | — | — |
| 1982 | 58° | 41° | 49° | — | — |
| 1981 | 61° | 52° | 56° | 0.25" | — |
| 1980 | 59° | 49° | 54° | — | — |
| 1979 | 55° | 38° | 46° | — | — |
| 1978 | 52° | 44° | 48° | 0.25" | — |
| 1977 | 58° | 42° | 50° | 0.28" | — |
| 1976 | 64° | 36° | 50° | — | — |
| 1975 | 65° | 37° | 51° | — | — |
| 1974 | 62° | 40° | 51° | — | — |
| 1973 | 63° | 45° | 54° | — | — |
| 1972 | 63° | 48° | 55° | 0.18" | — |
| 1971 | 57° | 39° | 48° | — | — |
55 years of data from MOFFETT FED AIRFIELD