December weather forecast
Valley Forge, PA

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Weather in December

December, the first month of the winter in Valley Forge, is also an icy month, with temperature in the range of an average high of 42.3°F (5.7°C) and an average low of 30.9°F (-0.6°C).

Temperature

Start of December brings a slight shift in the average high-temperature, dipping a bit from November's fresh 51.1°F (10.6°C) to a wintry 42.3°F (5.7°C). December in Valley Forge sees the temperature falling to a mean low of 30.9°F (-0.6°C).

Humidity

The average relative humidity in December is 79%.

Rainfall

In Valley Forge, during December, the rain falls for 7.9 days and regularly aggregates up to 0.98" (25mm) of precipitation. Throughout the year, there are 132.3 rainfall days, and 13.98" (355mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through March, November and December. In Valley Forge, Pennsylvania, in December, snow falls for 2.5 days, with typically accumulated 0.51" (13mm) of snow. In Valley Forge, Pennsylvania, during the entire year, snow falls for 15.1 days and aggregates up to 2.2" (56mm) of snow.

Daylight

With an average of 9h and 24min of daylight, December has the shortest days of the year in Valley Forge.
On the first day of December, sunrise is at 7:05 am and sunset at 4:36 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 4:46 pm EST.

Sunshine

The average sunshine in December in Valley Forge, Pennsylvania, is 4.8h.

UV index

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: The daily maximum UV index of 2 in December interprets into the following advice:
Extended exposure to the sun should always be avoided by children, infants, and those with sensitive skin. The Sun's radiation is especially intense around midday; try to stay in shade during this period. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun. Beware! Reflection from snow can magnify the Sun's UV radiation nearly twofold.
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Frequently asked questions

Is December cold in Valley Forge?

December temperatures in Valley Forge, Pennsylvania, vary between a high-temperature of 42.3°F (5.7°C) and a low-temperature of 30.9°F (-0.6°C). In August, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which combines air temperature and relative humidity, is estimated at 89.6°F (32°C).

What is the average humidity in December in Valley Forge?

The average relative humidity in December is 79%.

How many days does it rain in December in Valley Forge?

In Valley Forge, in December, during 7.9 rainfall days, 0.98" (25mm) of precipitation is typically accumulated.

How much does it snow in Valley Forge in December?

In Valley Forge, during December, snow falls for 2.5 days and regularly aggregates up to 0.51" (13mm) of snow.

What is the month with the shortest days in Valley Forge?

The month with the shortest days in Valley Forge is December, with an average of 9h and 24min of daylight.

What is the average length of the day in December in Valley Forge?

The average day length in December in Valley Forge is 9h and 23min.

What time are sunrise and sunset in December in Valley Forge?

On the first day of December in Valley Forge, Pennsylvania, sunrise is at 7:05 am and sunset at 4:36 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 4:46 pm EST.

How long on average sun shines in December in Valley Forge?

In Valley Forge, the average sunshine duration in December is 4.8h.

When is the lowest UV index in Valley Forge?

The months with the lowest UV index in Valley Forge, Pennsylvania, are January through March, November and December, with an average maximum UV index of 2.

What is the UV index intensity in December in Valley Forge?

In Valley Forge, the average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Valley Forge, PA

Average temperature in December - Valley Forge, PA
  • Average high temperature in December: 42.3°F

The warmest month (with the highest average high temperature) is July (85.1°F).
The month with the lowest average high temperature is January (36°F).

  • Average low temperature in December: 30.9°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (23.9°F).

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Average pressure in December
Valley Forge, PA

Average pressure in December - Valley Forge, PA
  • Average pressure in December: 30.1"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).

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Average wind speed in December
Valley Forge, PA

Average wind speed in December - Valley Forge, PA
  • Average wind speed in December: 7.7mph

The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).

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Average humidity in December
Valley Forge, PA

Average humidity in December - Valley Forge, PA
  • Average humidity in December: 79%

The month with the highest relative humidity is February (80%).
The months with the lowest relative humidity are April and July (74%).

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Average rainfall in December
Valley Forge, PA

Average rainfall in December - Valley Forge, PA
  • Average rainfall in December: 0.98"

The wettest month (with the highest rainfall) is August (1.77").
The driest month (with the least rainfall) is February (0.75").

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Average rainfall days in December
Valley Forge, PA

Average rainfall days in December - Valley Forge, PA
  • Average rainfall days in December: 7.9 days

The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is January (6.9 days).

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Average snowfall in December
Valley Forge, PA

Average snowfall in December - Valley Forge, PA
  • Average snowfall in December: 0.51"

The months with the highest snowfall are January and February (0.59").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in December
Valley Forge, PA

Average snowfall days in December - Valley Forge, PA
  • Average snowfall days in December: 2.5 days

The month with the highest number of snowfall days is February (4.9 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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Average daylight in December /
Average sunshine in December
Valley Forge, PA

Average daylight in December / Average sunshine in December - Valley Forge, 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: 4h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

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Average sunshine days in December
Valley Forge, PA

Average sunshine days in December - Valley Forge, PA
  • Average sunshine days in December: 20.4 days

The month with the most sunshine days is January (20.7 days).
The month with the least sunshine days is June (12.8 days).

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Average UV index in December
Valley Forge, PA

Average UV index in December - Valley Forge, 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, March, November and December (UV index 2).

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Average cloud cover in December
Valley Forge, PA

Average cloud cover in December - Valley Forge, PA
  • Average cloud cover in December: 48

The month with the most cloud cover is February (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 32).

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Average visibility in December
Valley Forge, PA

Average visibility in December - Valley Forge, PA
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, June, July, August, October, November and December (6mi).
The months with the lowest visibility are May and September (5mi).

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Valley Forge, Pennsylvania, USA

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