September weather in Philadelphia, PA
The average temperature in Philadelphia in September is 71.5°F (62.7°F–80.3°F). Average precipitation: 4.88 inches.
September is a fall month in Philadelphia, and is warmer than the annual average of 57.7°F. Daily temperatures swing about 17.6°F between overnight low and afternoon high. Expect about 9 days with precipitation. Daylight averages about 12h 15m. For travel, September is a comfortable month to visit.
Avg High
80.3°F
Avg Low
62.7°F
Precipitation
4.88 in
Daylight
12h 15m
September records in Philadelphia
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 98.1°F (2018) | 57.9°F (2009) | 1.45 in (2003) |
| September 2 | 98.1°F (2018) | 57.0°F (2017) | 2.61 in (2021) |
| September 3 | 93.9°F (1993) | 55.9°F (1994) | 0.86 in (2000) |
| September 4 | 97.0°F (2018) | 53.1°F (1997) | 0.77 in (2012) |
| September 5 | 97.0°F (2018) | 54.0°F (1994) | 1.67 in (2012) |
| September 6 | 96.1°F (2018) | 54.0°F (1994) | 2.90 in (2011) |
| September 7 | 96.1°F (2018) | 54.0°F (2000) | 3.98 in (2011) |
| September 8 | 99.0°F (2023) | 55.0°F (2024) | 2.76 in (2018) |
| September 9 | 96.1°F (2002) | 55.9°F (1998) | 1.69 in (2018) |
| September 10 | 97.0°F (2002) | 54.0°F (2017) | 2.30 in (2018) |
| September 11 | 88.0°F (2005) | 52.0°F (1993) | 2.80 in (2015) |
| September 12 | 93.9°F (2005) | 51.1°F (1993) | 0.69 in (2008) |
| September 13 | 98.1°F (2005) | 55.0°F (1994) | 0.50 in (2006) |
| September 14 | 93.0°F (2008) | 53.1°F (2014) | 1.96 in (2000) |
| September 15 | 90.0°F (2005) | 50.0°F (2001) | 2.47 in (1999) |
| September 16 | 93.9°F (2005) | 50.0°F (2008) | 5.58 in (1999) |
| September 17 | 91.9°F (2005) | 50.0°F (2013) | 2.68 in (1996) |
| September 18 | 89.1°F (2015) | 50.0°F (2013) | 1.63 in (1993) |
| September 19 | 91.9°F (2005) | 48.0°F (2020) | 1.58 in (2000) |
| September 20 | 89.1°F (2025) | 44.1°F (1993) | 0.83 in (1999) |
| September 21 | 89.1°F (1998) | 48.9°F (2020) | 0.74 in (1993) |
| September 22 | 91.0°F (2005) | 48.9°F (2020) | 1.20 in (2013) |
| September 23 | 93.0°F (2005) | 48.0°F (2020) | 2.47 in (2011) |
| September 24 | 91.9°F (2019) | 48.0°F (2013) | 2.16 in (2021) |
| September 25 | 93.0°F (2010) | 48.0°F (1997) | 2.12 in (2000) |
| September 26 | 90.0°F (2017) | 48.0°F (2000) | 2.67 in (1993) |
| September 27 | 93.0°F (1998) | 48.0°F (2000) | 0.57 in (2002) |
| September 28 | 89.1°F (2017) | 48.9°F (2001) | 7.50 in (2004) |
| September 29 | 87.1°F (2025) | 45.0°F (2000) | 0.86 in (1999) |
| September 30 | 87.1°F (2025) | 45.0°F (2000) | 5.59 in (2016) |