December weather forecast
Swarthmore, PA

Weather in December

The first month of the winter, December, is also a frosty month in Swarthmore, Pennsylvania, with an average temperature fluctuating between 32.9°F (0.5°C) and 44.1°F (6.7°C).

Temperature

In Swarthmore, the average high-temperature in December slightly decreases from a fresh 52.7°F (11.5°C) in November to a chilly 44.1°F (6.7°C). In Swarthmore, the average low-temperature is 32.9°F (0.5°C).

Humidity

The months with the highest humidity are February, October and December, with an average relative humidity of 77%.

Rainfall

In Swarthmore, during December, the rain falls for 8.7 days and regularly aggregates up to 2.32" (59mm) of precipitation. In Swarthmore, during the entire year, the rain falls for 148.4 days and collects up to 25.94" (659mm) of precipitation.

Snowfall

January through May, November and December are months with snowfall. In Swarthmore, in December, snow falls for 1.5 days, with typically accumulated 0.91" (23mm) of snow. In Swarthmore, Pennsylvania, during the entire year, snow falls for 12.6 days and aggregates up to 7.28" (185mm) of snow.

Daylight

With an average of 9h and 24min of daylight, December has the shortest days of the year in Swarthmore.
On the first day of December in Swarthmore, sunrise is at 7:03 am and sunset at 4:37 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:46 pm EST.

Sunshine

In Swarthmore, the average sunshine in December is 5.1h.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a low health risk from unprotected exposure to Sun's UV rays for average individuals.
Note: The daily maximum UV index of 2 in December interpret into the following 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. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the temperature in December in Swarthmore?

The average high-temperature, in December, in Swarthmore, is 44.1°F (6.7°C), while the average low-temperature is 32.9°F (0.5°C). The average heat index (a.k.a. 'felt air temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, in August is computed to be 89.6°F (32°C).

What are the most humid months in Swarthmore?

February, October and December, with an average relative humidity of 77%, are most humid months in Swarthmore, Pennsylvania.

What is the average humidity in December in Swarthmore?

In Swarthmore, Pennsylvania, the average relative humidity in December is 77%.

How many days does it rain in December in Swarthmore?

In December, the rain falls for 8.7 days. Throughout December, 2.32" (59mm) of precipitation is accumulated.

How much does it snow in Swarthmore in December?

In Swarthmore, Pennsylvania, in December, snow falls for 1.5 days, with typically accumulated 0.91" (23mm) of snow.

What is the month with the shortest days in Swarthmore?

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

What is the average length of the day in December in Swarthmore?

In Swarthmore, the average day length in December is 9h and 24min.

When are sunrise and sunset in December in Swarthmore?

In December, on the first day of the month, sunrise is at 7:03 am and sunset at 4:37 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:46 pm EST.

How long on average sun shines in December in Swarthmore?

In Swarthmore, the average sunshine duration in December is 5.1h.

When is the lowest UV index in Swarthmore?

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

How high is the UV index in December in Swarthmore?

In Swarthmore, Pennsylvania, the average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unsafe exposure to Sun's UV rays.
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
Swarthmore, PA

Average temperature in December - Swarthmore, PA
  • Average high temperature in December: 44.1°F

The warmest month (with the highest average high temperature) is July (85.6°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 (68.7°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).

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Average pressure in December
Swarthmore, PA

Average pressure in December - Swarthmore, 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).

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Average wind speed in December
Swarthmore, PA

Average wind speed in December - Swarthmore, PA
  • Average wind speed in December: 7.9mph

The windiest month (with the highest average wind speed) is March (8.6mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).

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Average humidity in December
Swarthmore, PA

Average humidity in December - Swarthmore, PA
  • Average humidity in December: 77%

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

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Average rainfall in December
Swarthmore, PA

Average rainfall in December - Swarthmore, PA
  • Average rainfall in December: 2.32"

The wettest month (with the highest rainfall) is August (3.11").
The driest month (with the least rainfall) is January (1.61").

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Average rainfall days in December
Swarthmore, PA

Average rainfall days in December - Swarthmore, PA
  • Average rainfall days in December: 8.7 days

The month with the highest number of rainy days is July (17 days).
The month with the least rainy days is January (7.1 days).

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Average snowfall in December
Swarthmore, PA

Average snowfall in December - Swarthmore, PA
  • Average snowfall in December: 0.91"

The month with the highest snowfall is March (2.32").
The months with the least snowfall are June, July, August, September and October (0").

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Average snowfall days in December
Swarthmore, PA

Average snowfall days in December - Swarthmore, PA
  • Average snowfall days in December: 1.5 days

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

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

Average daylight in December / Average sunshine in December - Swarthmore, PA
  • Average daylight in December: 9h and 24min

The month with the longest days is June (Average daylight: 14h and 58min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in December: 5h and 6min

The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 4h and 54min).

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Average sunshine days in December
Swarthmore, PA

Average sunshine days in December - Swarthmore, PA
  • Average sunshine days in December: 20.5 days

The month with the most sunshine days is January (20.8 days).
The month with the least sunshine days is July (11.3 days).

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Average UV index in December
Swarthmore, PA

Average UV index in December - Swarthmore, 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).

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Average cloud cover in December
Swarthmore, PA

Average cloud cover in December - Swarthmore, PA
  • Average cloud cover in December: 45

The month with the most cloud cover is February (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 30).

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Average visibility in December
Swarthmore, PA

Average visibility in December - Swarthmore, 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).

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