Contents
- 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
Weather in December
Temperature
The arrival of December corresponds with a minor reduction in the average high-temperature, down from November's fresh 52.7°F (11.5°C) to a chilly 44.1°F (6.7°C). Throughout December, an average low-temperature of 32.9°F (0.5°C) is expected.Humidity
The average relative humidity in December is 76%.Rainfall
In Philadelphia, during December, the rain falls for 7.5 days and regularly aggregates up to 1.18" (30mm) of precipitation. In Philadelphia, during the entire year, the rain falls for 127.8 days and collects up to 13.82" (351mm) of precipitation.Snowfall
Months with snowfall are January through May, November and December. In Philadelphia, in December, during 1.6 snowfall days, 0.2" (5mm) of snow is typically 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 December, the average ocean temperature is 47.8°F (8.8°C).Note: With the appropriate swimsuit, one can swim in 47.8°F (8.8°C) even if temperatures dip below 50°F (10°C); otherwise, be ready for cold shock and breath issues. A fleeting swim around 55.4°F (13°C) is distressing.
Daylight
December has the shortest days of the year, with an average of 9h and 24min of daylight.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
In December, the average sunshine 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 health risk from unsafe exposure to UV radiation for the average person.Note: During December, 2 as the daily maximum UV index converts into the following advice:
It is important to always shield children, babies, and individuals with sensitive skin from prolonged exposure to the sun. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses. Be vigilant! The reflective nature of snow can increase the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold does it get in December?
What is the average humidity in December in Philadelphia?
How much does it rain in December?
How many days does it snow in December?
What is the ocean temperature in December?
What is the month with the shortest days?
How many hours of daylight does Philadelphia have in December?
When are sunrise and sunset in December?
How long on average sun shines in December?
What are the months with the lowest UV index?
What is the UV index intensity in December?
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).
Philadelphia, Pennsylvania, USA
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