September weather in St. Marys, PA
The average temperature in St. Marys in September is 59.3°F (47.5°F–71.1°F). Average precipitation: 3.95 inches.
September is a fall month in St. Marys, and is warmer than the annual average of 45.1°F. Daily temperatures swing about 23.6°F between overnight low and afternoon high. Expect about 12 days with precipitation. Daylight averages about 12h 16m. For travel, September is a comfortable month to visit.
Avg High
71.1°F
Avg Low
47.5°F
Precipitation
3.95 in
Daylight
12h 16m
September records in St. Marys
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 86.0°F (2010) | 39.0°F (1970) | 1.80 in (1965) |
| September 2 | 86.0°F (2010) | 41.0°F (2009) | 1.69 in (2003) |
| September 3 | 89.1°F (2012) | 37.9°F (2024) | 1.75 in (1993) |
| September 4 | 91.9°F (2011) | 39.0°F (2024) | 0.90 in (1993) |
| September 5 | 84.9°F (2018) | 43.0°F (2010) | 0.96 in (2022) |
| September 6 | 87.1°F (2018) | 37.9°F (2013) | 1.44 in (1949) |
| September 7 | 88.0°F (2023) | 37.9°F (2013) | 1.56 in (2024) |
| September 8 | 87.1°F (2016) | 39.0°F (1955) | 1.95 in (1969) |
| September 9 | 86.0°F (2015) | 39.0°F (1955) | 3.24 in (2004) |
| September 10 | 82.9°F (2015) | 37.0°F (2017) | 1.50 in (2018) |
| September 11 | 86.0°F (2013) | 35.1°F (1969) | 0.78 in (1997) |
| September 12 | 86.0°F (2013) | 35.1°F (1969) | 0.71 in (2015) |
| September 13 | 82.9°F (2005) | 39.9°F (1969) | 2.03 in (1996) |
| September 14 | 82.0°F (2005) | 37.0°F (1955) | 2.10 in (1977) |
| September 15 | 82.0°F (2005) | 36.0°F (2020) | 1.97 in (1945) |
| September 16 | 82.0°F (1955) | 32.0°F (2011) | 1.14 in (1956) |
| September 17 | 84.9°F (1955) | 32.0°F (2011) | 0.99 in (1983) |
| September 18 | 88.0°F (1955) | 35.1°F (2007) | 3.10 in (2004) |
| September 19 | 91.0°F (1955) | 30.0°F (2020) | 1.51 in (1978) |
| September 20 | 89.1°F (1955) | 30.0°F (2020) | 2.21 in (1953) |
| September 21 | 82.0°F (2024) | 30.9°F (2020) | 1.12 in (1963) |
| September 22 | 82.9°F (2018) | 30.9°F (2020) | 3.05 in (1992) |
| September 23 | 82.0°F (1970) | 30.9°F (2020) | 2.19 in (2021) |
| September 24 | 84.9°F (2017) | 33.1°F (2013) | 2.50 in (1946) |
| September 25 | 86.0°F (2017) | 34.0°F (2013) | 1.37 in (1977) |
| September 26 | 86.0°F (2007) | 36.0°F (1955) | 1.27 in (1993) |
| September 27 | 84.9°F (2017) | 36.0°F (2016) | 1.29 in (2005) |
| September 28 | 86.0°F (2017) | 36.0°F (2016) | 2.05 in (1962) |
| September 29 | 79.0°F (2019) | 30.9°F (1969) | 3.85 in (1967) |
| September 30 | 75.9°F (2014) | 30.9°F (1969) | 2.21 in (1999) |