December weather forecast
Horsham, PA

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Weather in December

December, the first month of the winter in Horsham, is also a frosty month, with an average temperature ranging between min 31.1°F (-0.5°C) and max 42.8°F (6°C).

Temperature

December weather is marked by a drop in the average high-temperature, falling from a cool 51.8°F (11°C) in November to a frosty 42.8°F (6°C). The nighttime temperature, during December, averages of 31.1°F (-0.5°C).

Humidity

February, October and December, with an average relative humidity of 78%, are the most humid months.

Rainfall

December is the month with the most rainfall. Rain falls for 5.8 days and accumulates 0.75" (19mm) of precipitation.

Snowfall

Months with snowfall are January through May, November and December. In Horsham, in December, during 1.7 snowfall days, 0.28" (7mm) of snow is typically accumulated. In Horsham, during the entire year, snow falls for 12.6 days and aggregates up to 1.73" (44mm) 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 the month, sunrise is at 7:04 am and sunset at 4:35 pm. On the last day of December, sunrise is at 7:22 am and sunset at 4:44 pm EST.

Sunshine

The average sunshine in December is 5h.

UV index

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Horsham. A UV Index estimate of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV radiation for average individuals.
Note: The UV index of 2 in December translates into these instructions:
Most individuals face no major issues with lengthy exposure to the sun, but children, infants, and individuals with fair skin always require protection. The midday Sun can be dangerous due to its intense radiation; always find shade and reduce exposure. During bright days, sunglasses that offer UVA and UVB defense are recommended. Consider this! The reflection from snow can almost double the intensity of the Sun's UV radiation.
Updated: Aug 22, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in December?

December temperatures vary between a high-temperature of 42.8°F (6°C) and a low-temperature of 31.1°F (-0.5°C). In August, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, is computed to be 89.6°F (32°C).

What are the most humid months?

The months with the highest humidity are February, October and December, with an average relative humidity of 78%.

What is the average humidity in December?

In December, the average relative humidity is 78%.

What is the wettest month?

December is the month with the most rainfall. Rain falls for 5.8 days and accumulates 0.75" (19mm) of precipitation.

How much does it rain in December?

In Horsham, in December, during 5.8 rainfall days, 0.75" (19mm) of precipitation is typically accumulated.

How much does it snow in December?

In Horsham, during December, snow falls for 1.7 days and regularly aggregates up to 0.28" (7mm) of snow.

What is the month with the shortest days?

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

How many hours of daylight does Horsham have in December?

The average day length in December is 9h and 22min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:04 am and sunset at 4:35 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:44 pm EST.

How long on average sun shines in December?

In December, the average sunshine duration is 5h.

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.

How high is the UV index in December?

In Horsham, the average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a low health risk 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
Horsham, PA

Average temperature in December - Horsham, PA
  • Average high temperature in December: 42.8°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 (36.9°F).

  • Average low temperature in December: 31.1°F

The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).

Average pressure in December
Horsham, PA

Average pressure in December - Horsham, 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
Horsham, PA

Average wind speed in December - Horsham, PA
  • Average wind speed in December: 7.5mph

The windiest month (with the highest average wind speed) is March (8.4mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).

Average humidity in December
Horsham, PA

Average humidity in December - Horsham, PA
  • Average humidity in December: 78%

The months with the highest relative humidity are February, October and December (78%).
The months with the lowest relative humidity are April, July and August (72%).

Average rainfall in December
Horsham, PA

Average rainfall in December - Horsham, PA
  • Average rainfall in December: 0.75"

The wettest month (with the highest rainfall) is December (0.75").
The driest month (with the least rainfall) is September (0.2").

Average rainfall days in December
Horsham, PA

Average rainfall days in December - Horsham, PA
  • Average rainfall days in December: 5.8 days

The month with the highest number of rainy days is July (10.3 days).
The month with the least rainy days is January (4.3 days).

Average snowfall in December
Horsham, PA

Average snowfall in December - Horsham, PA
  • Average snowfall in December: 0.28"

The month with the highest snowfall is February (0.43").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days in December
Horsham, PA

Average snowfall days in December - Horsham, PA
  • Average snowfall days in December: 1.7 days

The month with the highest number of snowfall days is February (3.7 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Horsham, 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 42min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).

Average sunshine days in December
Horsham, PA

Average sunshine days in December - Horsham, PA
  • Average sunshine days in December: 23.2 days

The month with the most sunshine days is January (24.3 days).
The month with the least sunshine days is July (17.4 days).

Average UV index in December
Horsham, PA

Average UV index in December - Horsham, 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).

Average cloud cover in December
Horsham, PA

Average cloud cover in December - Horsham, PA
  • Average cloud cover in December: 47

The month with the most cloud cover is February (Cloud cover 48).
The month with the least cloud cover is July (Cloud cover 31).

Average visibility in December
Horsham, PA

Average visibility in December - Horsham, 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).

Horsham, Pennsylvania, USA

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