December weather - Winter 2024

Weather in December
Frequently asked questions
Average temperature in December
Average pressure in December
Average wind speed in December
Average humidity in December
Average rainfall in December
Average rainfall days in December
Average snowfall in December
Average snowfall days in December
Average sea temperature in December
Average daylight in December
Average sunshine in December
Average sunshine days in December
Average UV index in December
Average cloud cover in December
Average visibility in December

The George Washington statue in front of the Independence Hall in Philadelphia, Pennsylvania

Weather in December

Concluding the calendar year, December in Philadelphia, Pennsylvania sees the return of the winter season. The city witnesses a slight upsurge in snowfall to about 0.2" (5mm). Compared to November, December records an increase in rainfall at approximately 1.18" (30mm). Limited daylight hours and a growing chill in the air make it a perfect time for winter indoor festivities. Despite the cold weather, the holiday season sparkles, warming the hearts of city dwellers.

Temperature

The commencement of December includes a gentle temperature shift, with the average high-temperature dropping a bit from a cool 52.7°F (11.5°C) in November to a chilly 44.1°F (6.7°C). An average low-temperature of 32.9°F (0.5°C) is recorded in the month of December.

Humidity

In Philadelphia, the average relative humidity in December is 76%.

Rainfall

In December, in Philadelphia, the rain falls for 7.5 days. Throughout December, 1.18" (30mm) of precipitation is accumulated. Throughout the year, there are 127.8 rainfall days, and 13.82" (351mm) of precipitation is accumulated.

Snowfall

January through May, November and December are months with snowfall. In December, it is snowing for 1.6 days. Throughout December, 0.2" (5mm) of snow is accumulated. In Philadelphia, during the entire year, snow falls for 11.4 days and aggregates up to 2.87" (73mm) of snow.

Ocean temperature

In Philadelphia, the average seawater temperature in December is 47.8°F (8.8°C).
Note: Dipping in 47.8°F (8.8°C) at temperatures less than 50°F (10°C) without proper gear can lead to pronounced cold shock and breathing difficulties.

Daylight

With an average of 9h and 24min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 7:03 am and sunset at 4:36 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:45 pm EST.

Sunshine

The average sunshine in December is 5h.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In December, a daily maximum UV index of 2 leads to the following instructions:
Children, babies, and those with sensitive skin should always be shielded from long periods of sun exposure. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Be aware! The reflective nature of snow can magnify the Sun's UV radiation almost twofold.

Updated: Jun 4, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December in Philadelphia?

In Philadelphia, in December, the average high-temperature is 44.1°F (6.7°C), and the average low-temperature is 32.9°F (0.5°C). In August, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is computed to be 91.4°F (33°C).

What is the average humidity in December?

The average relative humidity in December in Philadelphia is 76%.

How many days does it rain in December?

In Philadelphia, during December, the rain falls for 7.5 days and regularly aggregates up to 1.18" (30mm) of precipitation.

How much does it snow in December?

In Philadelphia, in December, during 1.6 snowfall days, 0.2" (5mm) of snow is typically accumulated.

How cold is the water in December?

In Philadelphia, in December, the average water temperature is 47.8°F (8.8°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

What is the month with the shortest days?

With an average of 9h and 24min of daylight, December has the shortest days of the year.

How many hours of daylight does Philadelphia have in December?

In December, the average day length is 9h and 23min.

When are sunrise and sunset in December?

On the first day of December, sunrise is at 7:03 am and sunset at 4:36 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:45 pm EST.

How long on average sun shines in December?

The average sunshine duration in December is 5h.

What are the months with the lowest UV index in Philadelphia?

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index.

What is the UV index intensity in December?

In Philadelphia, the average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a low health threat from unsafe exposure to Sun's UV rays.

Today

Tomorrow

Long-term

Year J F M A M J J A S O N December

Nov

December

Jan

Average high temperature

52.7°F 11.5°C

44.1°F 6.7°C

37.4°F 3°C

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

8.1mph 13km/h

8.4mph 13.5km/h

8.9mph 14.3km/h

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

Average snowfall

Average snowfall days

0.3

1.6

3.8

Average sea temperature

Average daylight

Average sunshine

Average sunshine days

20.4

20.9

20.4

Average UV index

Average cloud cover

Average visibility

Average temperature in December
Philadelphia, PA

Average high temperature in December: 44.1°F

The warmest month (with the highest average high temperature) is July (86.4°F).
The month with the lowest average high temperature is January (37.4°F).

Average low temperature in December: 32.9°F

The month with the highest average low temperature is July (69.3°F).
The coldest month (with the lowest average low temperature) is January (25.5°F).

Average pressure in December
Philadelphia, PA

Average pressure in December: 30.09"Hg

The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in December
Philadelphia, PA

Average wind speed in December: 7.7mph

The windiest months (with the highest average wind speed) are March and April (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.6mph).

Average humidity in December
Philadelphia, PA

Average humidity in December: 76%

The month with the highest relative humidity is October (77%).
The months with the lowest relative humidity are April and August (71%).

Average rainfall in December
Philadelphia, PA

Average rainfall in December: 1.18"

The wettest month (with the highest rainfall) is August (1.65").
The driest months (with the least rainfall) are January and February (0.83").

Average rainfall days in December
Philadelphia, PA

Average rainfall days in December: 7.5 days

The month with the highest number of rainy days is July (14.8 days).
The month with the least rainy days is February (7.2 days).

Average snowfall in December
Philadelphia, PA

Average snowfall in December: 0.2"

The month with the highest snowfall is February (0.98").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days in December
Philadelphia, PA

Average snowfall days in December: 1.6 days

The month with the highest number of snowfall days is January (3.8 days).
The months with the least snowfall days are June, July, August, September and October (0 days).

Average sea temperature in December
Philadelphia, PA

Average sea temperature in December: 47.7°F

The best month for swimming (with the highest average sea temperature) is August (75.9°F).
The coldest month (with the lowest average sea temperature) is February (39.9°F).

Average daylight in December /
Average sunshine in December
Philadelphia, PA

Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

Average sunshine in December: 5h and 0min

The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).

Average sunshine days in December
Philadelphia, PA

Average sunshine days in December: 20.9 days

The month with the most sunshine days is December (20.9 days).
The month with the least sunshine days is May (13.3 days).

Average UV index in December
Philadelphia, PA

Average UV index in December: 2

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in December
Philadelphia, PA

Average cloud cover in December: 46

The months with the most cloud cover are February and March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 31).

Average visibility in December
Philadelphia, PA

Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

December weather forecast
Philadelphia, PA

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