Weather on September 4
Simi Valley, CA
55 Years of Data
Avg High
91°F
Avg Low
65°F
Warmest
2022
94°F avg
Coldest
2016
63°F avg
About This Date
September 4th in Simi Valley, CA typically brings hot fall weather, with average highs around 91°F and lows near 65°F — a 26°F daily swing. Over 30 years of records, the warmest September 4th was in 2022 (94°F average), while the coldest was 2016 (63°F) — a 31°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 5.6°F warmer on this date compared to 20-30 years ago.
The last decade has been 5.6°F warmer on this date compared to 20-30 years ago.
Planning for September 4th in Simi Valley, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
2.5°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 98° | 68° | 83° | — | — |
| 2024 | 100° | 76° | 88° | — | — |
| 2023 | 81° | 58° | 69° | — | — |
| 2022warmest | 108° | 80° | 94° | — | — |
| 2021 | 97° | 72° | 84° | — | — |
| 2020 | 102° | 69° | 86° | — | — |
| 2019 | 102° | 77° | 90° | — | — |
| 2018 | 88° | 60° | 74° | — | — |
| 2017 | 85° | 65° | 75° | — | — |
| 2016coldest | 72° | 55° | 63° | — | — |
| 2015 | 79° | 58° | 68° | — | — |
| 2014 | 85° | 59° | 72° | — | — |
| 2013 | 101° | 76° | 88° | — | — |
| 2012 | 91° | 63° | 77° | — | — |
| 2011 | 81° | 55° | 68° | — | — |
| 2010 | 95° | 69° | 82° | — | — |
| 2009 | 93° | 70° | 81° | — | — |
| 2008 | 90° | 64° | 77° | — | — |
| 2007 | 90° | 68° | 79° | — | — |
| 2006 | 91° | 66° | 79° | — | — |
| 2005 | 81° | 52° | 66° | — | — |
| 2004 | 91° | 57° | 74° | — | — |
| 2003 | 90° | 64° | 77° | — | — |
| 2002 | 98° | 66° | 82° | — | — |
| 2001 | 89° | 60° | 75° | — | — |
| 2000 | 85° | 59° | 72° | — | — |
| 1999 | 83° | 54° | 68° | — | — |
| 1998 | 77° | 66° | 72° | — | — |
| 1997 | 101° | 76° | 88° | — | — |
| 1996 | 91° | 61° | 76° | — | — |
30 years of data from SIMI VALLEY CALIFORNIA