September weather in Lake Forest Park, WA
The average temperature in Lake Forest Park in September is 62.3°F (53.2°F–71.3°F). Average precipitation: 1.74 inches.
September is a fall month in Lake Forest Park, and is warmer than the annual average of 53.2°F. Daily temperatures swing about 18.1°F between overnight low and afternoon high. Expect about 9 days with precipitation. Daylight averages about 12h 20m. For travel, September is one of the best months of the year to visit.
Avg High
71.3°F
Avg Low
53.2°F
Precipitation
1.74 in
Daylight
12h 20m
September records in Lake Forest Park
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 87.1°F (1987) | 48.0°F (1999) | 0.34 in (2004) |
| September 2 | 90.0°F (1988) | 46.9°F (1999) | 0.71 in (2016) |
| September 3 | 93.0°F (1988) | 48.0°F (1999) | 0.45 in (1996) |
| September 4 | 87.1°F (2017) | 48.0°F (2002) | 0.57 in (1995) |
| September 5 | 89.1°F (2024) | 46.9°F (2000) | 1.38 in (2013) |
| September 6 | 87.1°F (2014) | 46.9°F (2002) | 0.72 in (2009) |
| September 7 | 90.0°F (1993) | 44.1°F (1992) | 0.54 in (2019) |
| September 8 | 84.9°F (2011) | 50.0°F (2020) | 0.36 in (2010) |
| September 9 | 84.9°F (1993) | 48.9°F (1991) | 0.17 in (1994) |
| September 10 | 91.0°F (2020) | 46.0°F (1999) | 0.79 in (2019) |
| September 11 | 89.1°F (2013) | 48.0°F (1988) | 0.17 in (2003) |
| September 12 | 82.9°F (2009) | 48.0°F (1988) | 0.34 in (1997) |
| September 13 | 84.0°F (1999) | 48.9°F (1992) | 0.24 in (2004) |
| September 14 | 86.0°F (2000) | 46.9°F (1992) | 0.48 in (2006) |
| September 15 | 87.1°F (2014) | 45.0°F (1992) | 0.49 in (2019) |
| September 16 | 91.9°F (2025) | 43.0°F (1992) | 1.11 in (2003) |
| September 17 | 81.0°F (2012) | 46.9°F (1987) | 0.60 in (2021) |
| September 18 | 84.0°F (1991) | 45.0°F (1989) | 0.82 in (2010) |
| September 19 | 84.9°F (1999) | 46.9°F (1996) | 1.35 in (2020) |
| September 20 | 82.9°F (1987) | 45.0°F (2002) | 0.53 in (2008) |
| September 21 | 82.9°F (2014) | 44.1°F (2002) | 0.63 in (2025) |
| September 22 | 91.9°F (1990) | 44.1°F (2000) | 0.47 in (2019) |
| September 23 | 82.9°F (2009) | 43.0°F (2000) | 0.89 in (2020) |
| September 24 | 87.1°F (1997) | 42.1°F (2000) | 0.85 in (2020) |
| September 25 | 82.0°F (1991) | 44.1°F (2000) | 1.02 in (2023) |
| September 26 | 80.1°F (2022) | 46.0°F (2005) | 0.64 in (2021) |
| September 27 | 84.0°F (2017) | 43.0°F (1992) | 0.96 in (2023) |
| September 28 | 88.0°F (2017) | 44.1°F (1999) | 1.31 in (2013) |
| September 29 | 81.0°F (1992) | 44.1°F (2016) | 0.58 in (2000) |
| September 30 | 78.1°F (1987) | 39.9°F (2019) | 0.79 in (2007) |