December in Philadelphia is cold with some risk for some snow.
Temperatures
Daytime high temperatures during December tend to be around 48-50 F (9-10 C) early in the month, falling to 43-44 F (6-7 C) near the end of the month.
A few of the warmer afternoons, especially early in the month, can reach up near 63 F (17 C). The record high temperature recorded in Philadelphia during December is 73 F (22.8 C).

Late night and early morning low temperatures tend to fall from around 34-36 F (1-2 C) early in the month to about 29-30 F (-1 to -2 C) by the end of the month.
On average, about 17-18 days this month see temperatures at or below 32 F (0 C). A few of the colder mornings, especially late in the month can dip down to around 17-18 F (-8 C).
The record low temperature for Philadelphia during December is +1 F (-17.2 C).
Rain and Snow
You can expect about 7 sunny, 8 partly sunny, and 15 mostly cloudy days this month.
Measurable precipitation falls on about 11 days this month with 6-7 days recording at least 0.10 inches (2.5 mm) with 3 of these recording 0.5 inches (12.7 mm) or more.

Some snow falls, on average, on 2 days this month with snow accumulations of 3 inches (7.6 cm) or more occurring about once every 3 years and 5 inches (12.7 cm) or more about once every 5 years.
Daylight
The number of daylight hours remains fairly constant this month ranging from about 9.6 hours on the 1st to about 9.3 hours on the 21st.
Windspeed
Wind speeds are light to gentle at 4-12 mph (6-19 kph) but can briefly be moderate at 13-18 mph (20-28 kph) are 5-10 mph
What to Wear in Philadelphia during December?
Dress for winter as Philadelphia can be quite cold this month.
You should pack a Winter coat, warm hat, gloves, a few scarfs, some warm socks, and a couple of sweaters.
In addition, some thermals and at least one pair of waterproof boots will come in handy.
Things to Do in Philadelphia during December
Since it's bound to be cold outside in Philly this month, you might want to stay inside as much as possible, but there are also a lot of great lighting displays to see in this historic city.
If you're interested in seeing the lights and/or learning about the Christmas traditions in this city, we often provide a Philadelphia Holiday Tour during the month of December.
For even more family fun, make sure to read our post covering some of the best holiday celebrations in Philadelphia.
You might also want to look into a holiday musical or play, as there are usually several options for festive theatrical shows this month.
Alternatively, you can head out to the RiverRink Winterfest and have some fun ice skating!
There are so many interesting activities to consider that we actually made a post about the best things to do in Philadelphia in December, and you can find even more ideas in that article.
Fred Pickhardt