December weather forecast
Summerdale, PA

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Weather in December

The first month of the winter, December, is still a cold month in Summerdale, Pennsylvania, with temperature in the range of an average high of 41°F (5°C) and an average low of 29.7°F (-1.3°C).

Temperature

December's arrival comes with a decrease in the average high-temperature, moving from a cool 50°F (10°C) in November to a wintry 41°F (5°C). December witnesses an average nighttime temperature of 29.7°F (-1.3°C).

Humidity

In December, the average relative humidity is 79%.

Rainfall

In Summerdale, during December, the rain falls for 8.4 days and regularly aggregates up to 0.87" (22mm) of precipitation. Throughout the year, there are 122.3 rainfall days, and 11.73" (298mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, November and December. In Summerdale, during December, snow falls for 3.5 days and regularly aggregates up to 0.59" (15mm) of snow. Throughout the year, there are 19.9 snowfall days, and 4.29" (109mm) of snow is accumulated.

Daylight

With an average of 9h and 24min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:11 am and sunset at 4:42 pm. On the last day of December, sunrise is at 7:30 am and sunset at 4:51 pm EST.

Sunshine

The average sunshine in December is 4.7h.

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 reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In December, the maximum UV index of 2 transforms into these recommendations:
Most people face no serious problems with extended sun exposure, but those with fair skin, infants, and children always need protection. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Updated: Jul 25, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is it cold in Summerdale during December?

During December, Summerdale experiences an average high-temperature of 41°F (5°C) and a low-temperature of 29.7°F (-1.3°C). The average heat index (a.k.a. 'real feel', 'apparent temperature'), which factors the actual air temperature with the relative humidity, in August is evaluated at 87.8°F (31°C).

What is the average humidity in December?

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

How much does it rain in December?

In Summerdale, during December, the rain falls for 8.4 days and regularly aggregates up to 0.87" (22mm) of precipitation.

How many days does it snow in December?

In Summerdale, in December, snow falls for 3.5 days, with typically accumulated 0.59" (15mm) of snow.

What is the month with the shortest days?

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

What is the average length of the day in December?

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

What time are sunrise and sunset in December?

On the first day of December, sunrise is at 7:11 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 7:30 am and sunset at 4:51 pm EST.

How long on average sun shines in December?

In Summerdale, the average sunshine duration in December is 4.7h.

What is the month 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 is 2. A UV Index value of 2, and less, symbolizes a low health threat from unsafe exposure to Sun's UV rays.
Average high temperature
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
Summerdale, PA

Average temperature in December - Summerdale, PA
  • Average high temperature in December: 41°F

The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (35.1°F).

  • Average low temperature in December: 29.7°F

The month with the highest average low temperature is July (63.5°F).
The coldest month (with the lowest average low temperature) is January (22.1°F).

Average pressure in December
Summerdale, PA

Average pressure in December - Summerdale, 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 (29.95"Hg).

Average wind speed in December
Summerdale, PA

Average wind speed in December - Summerdale, PA
  • Average wind speed in December: 7.6mph

The windiest month (with the highest average wind speed) is March (8.2mph).
The calmest months (with the lowest average wind speed) are July and August (4.8mph).

Average humidity in December
Summerdale, PA

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

The month with the highest relative humidity is February (80%).
The months with the lowest relative humidity are March and April (75%).

Average rainfall in December
Summerdale, PA

Average rainfall in December - Summerdale, PA
  • Average rainfall in December: 0.87"

The wettest month (with the highest rainfall) is August (1.3").
The driest months (with the least rainfall) are January and February (0.71").

Average rainfall days in December
Summerdale, PA

Average rainfall days in December - Summerdale, PA
  • Average rainfall days in December: 8.4 days

The month with the highest number of rainy days is May (13.9 days).
The month with the least rainy days is January (5.7 days).

Average snowfall in December
Summerdale, PA

Average snowfall in December - Summerdale, PA
  • Average snowfall in December: 0.59"

The month with the highest snowfall is February (1.3").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in December
Summerdale, PA

Average snowfall days in December - Summerdale, PA
  • Average snowfall days in December: 3.5 days

The month with the highest number of snowfall days is January (6.3 days).
The months with the least snowfall days are June, July, August, September and October (0 days).

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

Average daylight in December / Average sunshine in December - Summerdale, 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 4min

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 30min).

Average sunshine days in December
Summerdale, PA

Average sunshine days in December - Summerdale, PA
  • Average sunshine days in December: 20.2 days

The month with the most sunshine days is November (21.8 days).
The month with the least sunshine days is July (14.1 days).

Average UV index in December
Summerdale, PA

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

The months with the highest UV index are May, June and July (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
Summerdale, PA

Average cloud cover in December - Summerdale, PA
  • Average cloud cover in December: 50

The months with the most cloud cover are February and December (Cloud cover 50).
The month with the least cloud cover is July (Cloud cover 31).

Average visibility in December
Summerdale, PA

Average visibility in December - Summerdale, 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).

Summerdale, Pennsylvania, USA

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