December weather forecast
Penryn, PA

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Weather in December

The first month of the winter, December, is still a cold month in Penryn, Pennsylvania, with an average temperature ranging between max 41.5°F (5.3°C) and min 30°F (-1.1°C).

Temperature

The arrival of December corresponds with a minor reduction in the average high-temperature, down from November's cool 50.4°F (10.2°C) to a cold 41.5°F (5.3°C). In Penryn, the nighttime temperature averages to a subzero cold 30°F (-1.1°C) during December.

Humidity

In Penryn, the average relative humidity in December is 79%.

Rainfall

In December, the rain falls for 11.3 days. Throughout December, 2.36" (60mm) of precipitation is accumulated. In Penryn, during the entire year, the rain falls for 161.8 days and collects up to 30.31" (770mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall. In Penryn, in December, snow falls for 3.8 days, with typically accumulated 1.57" (40mm) of snow. In Penryn, during the entire year, snow falls for 24.1 days and aggregates up to 11.93" (303mm) of snow.

Daylight

The month with the shortest days is December, with an average of 9h and 24min of daylight.
On the first day of December, sunrise is at 7:09 am and sunset at 4:40 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 4:49 pm EST.

Sunshine

The average sunshine in December 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 health risk from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In December, the maximum UV index of 2 suggests this advice:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. Minimize direct exposure to the Sun during midday when its radiation is at its peak. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Be mindful! The reflection from snow can increase the Sun's UV radiation nearly twice.

Frequently asked questions

How cold is December?

During December, Penryn experiences an average high-temperature of 41.5°F (5.3°C) and a low-temperature of 30°F (-1.1°C). In August, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which represents the influence of relative humidity on air temperature, is estimated at 86°F (30°C).

What is the average humidity in December?

In Penryn, the average relative humidity in December is 79%.

How much does it rain in December?

In Penryn, during December, the rain falls for 11.3 days and regularly aggregates up to 2.36" (60mm) of precipitation.

How many days does it snow in December?

In Penryn, in December, during 3.8 snowfall days, 1.57" (40mm) of snow is typically accumulated.

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 Penryn have in December?

In December, the average day length is 9h and 22min.

What time are sunrise and sunset in December?

On the first day of December, sunrise is at 7:09 am and sunset at 4:40 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 4:49 pm EST.

How many hours of sunshine does Penryn have in December?

In December, the average sunshine duration is 4.8h.

What are the months with the lowest UV index?

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

What is the UV index reading in December?

The average daily maximum UV index in December in Penryn is 2. A UV Index value of 2, and less, symbolizes a minimal hazard to health 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
Penryn, PA

Average temperature in December - Penryn, PA
  • Average high temperature in December: 41.5°F

The warmest month (with the highest average high temperature) is July (82.6°F).
The month with the lowest average high temperature is January (35.4°F).

  • Average low temperature in December: 30°F

The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (22.8°F).

Average pressure in December
Penryn, PA

Average pressure in December - Penryn, PA
  • Average pressure in December: 30.1"Hg

The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in December
Penryn, PA

Average wind speed in December - Penryn, PA
  • Average wind speed in December: 8.3mph

The windiest month (with the highest average wind speed) is March (8.9mph).
The calmest month (with the lowest average wind speed) is August (5mph).

Average humidity in December
Penryn, PA

Average humidity in December - Penryn, PA
  • Average humidity in December: 79%

The month with the highest relative humidity is May (81%).
The month with the lowest relative humidity is April (76%).

Average rainfall in December
Penryn, PA

Average rainfall in December - Penryn, PA
  • Average rainfall in December: 2.36"

The wettest month (with the highest rainfall) is August (3.31").
The driest month (with the least rainfall) is February (2.09").

Average rainfall days in December
Penryn, PA

Average rainfall days in December - Penryn, PA
  • Average rainfall days in December: 11.3 days

The month with the highest number of rainy days is July (17.3 days).
The month with the least rainy days is January (9 days).

Average snowfall in December
Penryn, PA

Average snowfall in December - Penryn, PA
  • Average snowfall in December: 1.57"

The month with the highest snowfall is March (3.43").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Penryn, PA

Average snowfall days in December - Penryn, PA
  • Average snowfall days in December: 3.8 days

The month with the highest number of snowfall days is January (7.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Penryn, 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 36min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

Average sunshine days in December
Penryn, PA

Average sunshine days in December - Penryn, PA
  • Average sunshine days in December: 16.2 days

The month with the most sunshine days is November (17.8 days).
The months with the least sunshine days are May and July (11.6 days).

Average UV index in December
Penryn, PA

Average UV index in December - Penryn, PA
  • Average UV index in December: 2

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

Average cloud cover in December
Penryn, PA

Average cloud cover in December - Penryn, PA
  • Average cloud cover in December: 49

The months with the most cloud cover are February and December (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 31).

Average visibility in December
Penryn, PA

Average visibility in December - Penryn, PA
  • Average visibility in December: 6mi

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

Penryn, Pennsylvania, USA

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