September weather in Deer Park, WA
The average temperature in Deer Park in September is 57.0°F (39.9°F–74.0°F). Average precipitation: 0.82 inches.
September is a fall month in Deer Park, and is warmer than the annual average of 45.6°F. Daily temperatures swing about 34.1°F between overnight low and afternoon high. Expect about 6 days with precipitation. Daylight averages about 12h 20m. For travel, September is a comfortable month to visit.
Avg High
74.0°F
Avg Low
39.9°F
Precipitation
0.82 in
Daylight
12h 20m
September records in Deer Park
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 99.0°F (2025) | 28.9°F (1999) | 0.04 in (2004) |
| September 2 | 100.0°F (2025) | 33.1°F (2011) | 0.18 in (2000) |
| September 3 | 99.0°F (2025) | 33.1°F (2011) | 0.28 in (2014) |
| September 4 | 93.0°F (2003) | 32.0°F (1999) | 0.07 in (2013) |
| September 5 | 96.1°F (2024) | 30.9°F (2005) | 0.61 in (2013) |
| September 6 | 95.0°F (2024) | 30.9°F (2001) | 0.19 in (2013) |
| September 7 | 96.1°F (2024) | 28.9°F (1999) | 0.19 in (2003) |
| September 8 | 91.9°F (2011) | 28.9°F (2001) | 1.04 in (2003) |
| September 9 | 96.1°F (2011) | 27.0°F (2000) | 0.36 in (2019) |
| September 10 | 93.9°F (2011) | 32.0°F (2007) | 0.23 in (2000) |
| September 11 | 93.0°F (2011) | 25.0°F (2012) | 0.67 in (2004) |
| September 12 | 91.9°F (2013) | 24.1°F (2012) | 0.14 in (2005) |
| September 13 | 90.0°F (2001) | 30.0°F (2003) | 0.13 in (2004) |
| September 14 | 90.0°F (2002) | 28.9°F (2006) | 0.15 in (2025) |
| September 15 | 89.1°F (2001) | 32.0°F (2008) | 0.27 in (2004) |
| September 16 | 91.0°F (2009) | 27.0°F (2006) | 0.07 in (2019) |
| September 17 | 89.1°F (2008) | 28.0°F (2006) | 0.29 in (2002) |
| September 18 | 86.0°F (2008) | 32.0°F (2003) | 0.38 in (2017) |
| September 19 | 90.0°F (2008) | 33.1°F (2004) | 0.42 in (2010) |
| September 20 | 84.9°F (2012) | 27.0°F (2007) | 0.19 in (2006) |
| September 21 | 88.0°F (2012) | 26.1°F (2009) | 0.77 in (2008) |
| September 22 | 84.9°F (1999) | 23.0°F (2000) | 0.07 in (2013) |
| September 23 | 90.0°F (2001) | 18.0°F (2000) | 0.23 in (2020) |
| September 24 | 93.0°F (2011) | 21.0°F (2000) | 0.11 in (2013) |
| September 25 | 89.1°F (2024) | 24.1°F (2000) | 0.71 in (2020) |
| September 26 | 84.9°F (2022) | 28.0°F (2000) | 0.31 in (2019) |
| September 27 | 89.1°F (2022) | 26.2°F (2015) | 0.56 in (2023) |
| September 28 | 84.0°F (2024) | 23.0°F (2005) | 0.75 in (2013) |
| September 29 | 82.0°F (2006) | 28.0°F (2001) | 0.23 in (2013) |
| September 30 | 82.0°F (2015) | 24.1°F (2009) | 0.43 in (2005) |