December weather in St. Marys, PA
The average temperature in St. Marys in December is 27.1°F (19.7°F–34.5°F). Average precipitation: 3.60 inches. Average snowfall is 14.2 inches.
December is a winter month in St. Marys, and is cooler than the annual average of 45.1°F. Daily temperatures swing about 14.8°F between overnight low and afternoon high. Expect about 18 days with precipitation. Daylight averages about 9h 1m. For travel, December is cold.
Avg High
34.5°F
Avg Low
19.7°F
Precipitation
3.60 in
Snow
14.2 in
December records in St. Marys
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| December 1 | 64.9°F (2010) | 9.0°F (2013) | 3.11 in (2010) |
| December 2 | 62.1°F (2006) | 10.0°F (1964) | 0.76 in (2019) |
| December 3 | 54.0°F (1970) | 7.0°F (2003) | 1.74 in (1991) |
| December 4 | 57.0°F (1973) | 7.0°F (2003) | 1.07 in (1968) |
| December 5 | 66.0°F (2012) | 10.9°F (2003) | 0.81 in (1994) |
| December 6 | 57.0°F (1973) | 1.0°F (2007) | 1.01 in (1977) |
| December 7 | 48.9°F (2011) | 5.0°F (2007) | 1.25 in (1962) |
| December 8 | 50.0°F (2004) | 3.9°F (2005) | 0.77 in (1969) |
| December 9 | 51.1°F (2012) | 3.9°F (2005) | 1.25 in (1978) |
| December 10 | 54.0°F (2023) | 5.0°F (1964) | 1.38 in (1975) |
| December 11 | 57.0°F (2024) | 6.1°F (1964) | 1.68 in (1992) |
| December 12 | 59.0°F (2021) | 6.1°F (2013) | 1.26 in (1964) |
| December 13 | 57.9°F (2015) | -4.0°F (2005) | 0.75 in (1948) |
| December 14 | 61.0°F (2015) | -0.9°F (2005) | 0.68 in (2002) |
| December 15 | 62.1°F (2015) | -0.9°F (2005) | 1.43 in (1977) |
| December 16 | 53.1°F (2011) | -0.9°F (2005) | 0.79 in (2022) |
| December 17 | 57.0°F (2021) | -0.9°F (2016) | 0.94 in (2020) |
| December 18 | 55.0°F (2006) | 6.1°F (1973) | 1.22 in (2001) |
| December 19 | 48.9°F (2006) | 3.9°F (2010) | 0.79 in (1990) |
| December 20 | 45.0°F (2017) | -9.0°F (2004) | 0.91 in (1995) |
| December 21 | 51.1°F (2013) | -9.9°F (2004) | 0.94 in (2012) |
| December 22 | 60.1°F (2013) | -2.9°F (2008) | 2.00 in (1998) |
| December 23 | 57.9°F (2013) | -2.0°F (2024) | 0.82 in (2022) |
| December 24 | 57.0°F (2015) | -8.0°F (2022) | 0.94 in (2007) |
| December 25 | 59.0°F (2015) | -4.0°F (2022) | 1.60 in (1978) |
| December 26 | 55.9°F (2015) | 1.0°F (2013) | 0.93 in (1957) |
| December 27 | 55.0°F (1964) | -2.0°F (2017) | 1.50 in (2012) |
| December 28 | 57.9°F (2015) | -7.1°F (2017) | 1.17 in (1968) |
| December 29 | 59.0°F (2008) | -8.0°F (2017) | 0.57 in (1959) |
| December 30 | 59.0°F (2024) | 3.0°F (2017) | 1.66 in (1942) |
| December 31 | 55.0°F (2022) | -6.0°F (2017) | 1.26 in (1971) |