Weather on June 21
Simi Valley, CA
55 Years of Data
About This Date
June 21st in Simi Valley, CA typically brings warm summer weather, with average highs around 83°F and lows near 58°F — a 25°F daily swing. Over 30 years of records, the warmest June 21st was in 2017 (88°F average), while the coldest was 2003 (59°F) — a 29°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 5.8°F warmer on this date compared to 20-30 years ago.
The last decade has been 5.8°F warmer on this date compared to 20-30 years ago.
Planning for June 21st in Simi Valley, CA? Stay hydrated and seek shade during peak afternoon hours.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 76° | 57° | 66° | — | — |
| 2024 | 88° | 59° | 73° | — | — |
| 2023 | 80° | 57° | 69° | — | — |
| 2022 | 92° | 69° | 80° | — | — |
| 2021 | 91° | 55° | 73° | — | — |
| 2020 | 83° | 56° | 69° | — | — |
| 2019 | 67° | 56° | 61° | — | — |
| 2018 | 87° | 58° | 72° | — | — |
| 2017warmest | 104° | 71° | 88° | — | — |
| 2016 | 95° | 70° | 82° | — | — |
| 2015 | 91° | 64° | 78° | — | — |
| 2014 | 95° | 60° | 78° | — | — |
| 2013 | 86° | 60° | 73° | — | — |
| 2012 | 70° | 55° | 62° | — | — |
| 2011 | 82° | 55° | 69° | — | — |
| 2010 | 73° | 50° | 62° | — | — |
| 2009 | 70° | 55° | 62° | — | — |
| 2008 | 100° | 73° | 87° | — | — |
| 2007 | 82° | 57° | 70° | — | — |
| 2006 | 79° | 54° | 66° | — | — |
| 2005 | 84° | 55° | 70° | — | — |
| 2004 | 72° | 55° | 63° | — | — |
| 2003coldest | 64° | 54° | 59° | — | — |
| 2002 | 70° | 55° | 62° | — | — |
| 2001 | 97° | 67° | 82° | — | — |
| 2000 | 86° | 59° | 73° | — | — |
| 1999 | 77° | 54° | 65° | — | — |
| 1998 | 81° | 53° | 67° | — | — |
| 1997 | 82° | 55° | 69° | — | — |
| 1996 | 78° | 52° | 65° | — | — |
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.