Weather on December 15
Simi Valley, CA
55 Years of Data
Avg High
64°F
Avg Low
46°F
Warmest
2017
71°F avg
Coldest
2004
18°F avg
About This Date
December 15th in Simi Valley, CA typically brings mild winter weather, with average highs around 64°F and lows near 46°F. Over 31 years of records, the warmest December 15th was in 2017 (71°F average), while the coldest was 2004 (18°F) — a 53°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 5.5°F warmer on this date compared to 20-30 years ago.
The last decade has been 5.5°F warmer on this date compared to 20-30 years ago.
Planning for December 15th in Simi Valley, CA? Great weather for outdoor activities.
Warming Trend
1.4°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 77° | 62° | 70° | — | — |
| 2024 | 65° | 47° | 56° | — | — |
| 2023 | 74° | 55° | 64° | — | — |
| 2022 | 59° | 48° | 54° | — | — |
| 2021 | 55° | 39° | 47° | — | — |
| 2020 | 62° | 49° | 55° | — | — |
| 2019 | 55° | 44° | 50° | — | — |
| 2018 | 73° | 59° | 66° | — | — |
| 2017warmest | 82° | 61° | 71° | — | — |
| 2016 | 62° | 47° | 54° | — | — |
| 2015 | 56° | 41° | 48° | — | — |
| 2014 | 58° | 48° | 53° | — | — |
| 2013 | 77° | 61° | 69° | — | — |
| 2012 | 58° | 40° | 49° | — | — |
| 2011 | 55° | 39° | 47° | — | — |
| 2010 | 55° | 50° | 53° | — | — |
| 2009 | 66° | 49° | 57° | — | — |
| 2008 | 48° | 45° | 46° | — | — |
| 2007 | 66° | 45° | 55° | — | — |
| 2006 | 66° | 48° | 57° | — | — |
| 2005 | 64° | 50° | 57° | — | — |
| 2004coldest | 75° | -40° | 18° | — | — |
| 2003 | 61° | 46° | 53° | — | — |
| 2002 | 61° | 50° | 55° | — | — |
| 2001 | 55° | 45° | 50° | — | — |
| 2000 | 68° | 51° | 60° | — | — |
| 1999 | 67° | 51° | 59° | — | — |
| 1998 | 75° | 59° | 67° | — | — |
| 1997 | 64° | 47° | 55° | — | — |
| 1996 | 62° | 53° | 58° | — | — |
| 1995 | 67° | 49° | 58° | — | — |
31 years of data from SIMI VALLEY CALIFORNIA