Weather on April 21
Simi Valley, CA
55 Years of Data
Avg High
74°F
Avg Low
51°F
Warmest
2009
79°F avg
Coldest
2001
48°F avg
About This Date
April 21st in Simi Valley, CA typically brings pleasant spring weather, with average highs around 74°F and lows near 51°F. Over 30 years of records, the warmest April 21st was in 2009 (79°F average), while the coldest was 2001 (48°F) — a 31°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 4.5°F warmer on this date compared to 20-30 years ago.
The last decade has been 4.5°F warmer on this date compared to 20-30 years ago.
Planning for April 21st in Simi Valley, CA? Great weather for outdoor activities.
Warming Trend
1.6°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 78° | 50° | 64° | — | — |
| 2024 | 81° | 53° | 67° | — | — |
| 2023 | 88° | 63° | 75° | — | — |
| 2022 | 66° | 46° | 56° | — | — |
| 2021 | 59° | 49° | 54° | — | — |
| 2020 | 77° | 50° | 64° | — | — |
| 2019 | 69° | 49° | 59° | — | — |
| 2018 | 88° | 56° | 72° | — | — |
| 2017 | 89° | 60° | 75° | — | — |
| 2016 | 85° | 52° | 68° | — | — |
| 2015 | 62° | 49° | 55° | — | — |
| 2014 | 86° | 57° | 72° | — | — |
| 2013 | 91° | 55° | 73° | — | — |
| 2012 | 81° | 50° | 65° | — | — |
| 2011 | 61° | 50° | 55° | — | — |
| 2010 | 56° | 41° | 48° | — | — |
| 2009warmest | 93° | 64° | 79° | — | — |
| 2008 | 64° | 41° | 53° | — | — |
| 2007 | 63° | 43° | 53° | — | — |
| 2006 | 66° | 50° | 58° | — | — |
| 2005 | 73° | 46° | 60° | — | — |
| 2004 | 68° | 48° | 58° | — | — |
| 2003 | 59° | 46° | 53° | — | — |
| 2002 | 73° | 45° | 59° | — | — |
| 2001coldest | 56° | 40° | 48° | — | — |
| 2000 | 63° | 51° | 57° | — | — |
| 1999 | 74° | 50° | 62° | — | — |
| 1998 | 90° | 61° | 75° | — | — |
| 1997 | 88° | 66° | 77° | — | — |
| 1996 | 71° | 49° | 60° | — | — |
30 years of data from SIMI VALLEY CALIFORNIA