Weather on September 17
Simi Valley, CA
55 Years of Data
About This Date
September 17th in Simi Valley, CA typically brings warm fall weather, with average highs around 83°F and lows near 60°F. Over 31 years of records, the warmest September 17th was in 2020 (87°F average), while the coldest was 2024 (62°F) — a 25°F range across recorded history. This date has historically been dry, with little recorded precipitation. Temperatures on this date have remained relatively stable over the past several decades.
Temperatures on this date have remained relatively stable over the past several decades.
Planning for September 17th in Simi Valley, CA? Stay hydrated and seek shade during peak afternoon hours.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2026 | 80° | 59° | 70° | — | — |
| 2025 | 93° | 66° | 80° | — | — |
| 2024coldest | 72° | 52° | 62° | — | — |
| 2023 | 69° | 59° | 64° | — | — |
| 2022 | 78° | 58° | 68° | — | — |
| 2021 | 82° | 52° | 67° | — | — |
| 2020warmest | 98° | 75° | 87° | — | — |
| 2019 | 85° | 59° | 72° | — | — |
| 2018 | 92° | 64° | 78° | — | — |
| 2017 | 78° | 57° | 68° | — | — |
| 2016 | 95° | 64° | 80° | — | — |
| 2015 | 81° | 61° | 71° | — | — |
| 2014 | 98° | 68° | 83° | — | — |
| 2013 | 88° | 61° | 74° | — | — |
| 2012 | 79° | 57° | 68° | — | — |
| 2011 | 73° | 57° | 65° | — | — |
| 2010 | 75° | 51° | 63° | — | — |
| 2009 | 87° | 61° | 74° | — | — |
| 2008 | 79° | 57° | 68° | — | — |
| 2007 | 70° | 57° | 63° | — | — |
| 2006 | 91° | 61° | 76° | — | — |
| 2005 | 75° | 54° | 64° | — | — |
| 2004 | 77° | 57° | 67° | — | — |
| 2003 | 75° | 54° | 64° | — | — |
| 2002 | 77° | 55° | 66° | — | — |
| 2001 | 83° | 56° | 69° | — | — |
| 2000 | 100° | 67° | 83° | — | — |
| 1999 | 84° | 56° | 70° | — | — |
| 1998 | 92° | 66° | 79° | — | — |
| 1997 | 88° | 69° | 78° | — | — |
| 1996 | 92° | 57° | 74° | — | — |
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.
What to expect on September 17th
This page shows what actually happened each year. For the odds — typical high and low, and how often it stays dry — see the climatological outlook for this date.
September 17th outlook →