Weather on December 31
Simi Valley, CA
55 Years of Data
About This Date
December 31st in Simi Valley, CA typically brings mild winter weather, with average highs around 62°F and lows near 48°F. Over 30 years of records, the warmest December 31st was in 1997 (69°F average), while the coldest was 2014 (42°F) — a 27°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 1.9°F cooler on this date compared to 20-30 years ago.
The last decade has been 1.9°F cooler on this date compared to 20-30 years ago.
Planning for December 31st in Simi Valley, CA? Great weather for outdoor activities.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 64° | 50° | 57° | — | — |
| 2024 | 70° | 49° | 59° | — | — |
| 2022 | 54° | 51° | 52° | — | — |
| 2021 | 60° | 43° | 51° | — | — |
| 2020 | 58° | 48° | 53° | — | — |
| 2019 | 61° | 53° | 57° | — | — |
| 2018 | 56° | 45° | 50° | — | — |
| 2017 | 71° | 53° | 62° | — | — |
| 2016 | 50° | 41° | 46° | — | — |
| 2015 | 57° | 45° | 51° | — | — |
| 2014coldest | 47° | 37° | 42° | — | — |
| 2013 | 78° | 56° | 67° | — | — |
| 2012 | 58° | 41° | 49° | — | — |
| 2011 | 79° | 48° | 63° | — | — |
| 2010 | 54° | 39° | 46° | — | — |
| 2009 | 62° | 46° | 54° | — | — |
| 2008 | 66° | 45° | 55° | — | — |
| 2007 | 64° | 54° | 59° | — | — |
| 2006 | 59° | 39° | 49° | — | — |
| 2005 | 57° | 48° | 53° | — | — |
| 2004 | 55° | 48° | 52° | — | — |
| 2003 | 63° | 41° | 52° | — | — |
| 2002 | 55° | 43° | 49° | — | — |
| 2001 | 59° | 52° | 55° | — | — |
| 2000 | 75° | 55° | 65° | — | — |
| 1999 | 52° | 44° | 48° | — | — |
| 1998 | 69° | 50° | 60° | — | — |
| 1997warmest | 79° | 60° | 69° | — | — |
| 1996 | 63° | 52° | 57° | — | — |
| 1995 | 64° | 61° | 62° | — | — |
Simi Valley, CA Temperature Range by Month
Average monthly highs and lows. The shaded band shows the typical daily temperature range.
Simi Valley, CA Daily Temperature Calendar
Average daily high temperature for every day of the year. Each cell is the climatological mean for that calendar day across 55 years of NOAA data.
Best Time to Visit Simi Valley, CA
Most pleasant months in Simi Valley, CA: January, March, April, May, June, October, November.