December weather forecast
Riverdale Heights, MD

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Weather in December

The first month of the winter, December, is also a frosty month in Riverdale Heights, Maryland, with an average temperature fluctuating between 34.3°F (1.3°C) and 45.5°F (7.5°C).

Temperature

December signifies a gentle decline in Riverdale Heights's average high-temperature, easing from a fresh 54.1°F (12.3°C) in November to a frosty 45.5°F (7.5°C). Throughout December, Riverdale Heights anticipates an average low-temperature of 34.3°F (1.3°C).

Humidity

May, October and December, with an average relative humidity of 76%, are the most humid months.

Rainfall

In Riverdale Heights, during December, the rain falls for 9.8 days and regularly aggregates up to 2.6" (66mm) of precipitation. Throughout the year, there are 157.9 rainfall days, and 31.14" (791mm) of precipitation is accumulated.

Snowfall

January through April and December are months with snowfall. December is the first month it typically snows in Riverdale Heights. Throughout December, in the average 2.4 snowfall days, it receives 0.67" (17mm) of snow. Throughout the year, in Riverdale Heights, there are 13.5 snowfall days, and 7.2" (183mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 9h and 30min of daylight.
On the first day of December, sunrise is at 7:08 am and sunset at 4:45 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 4:55 pm EST.

Sunshine

In Riverdale Heights, the average sunshine in December is 5.1h.

UV index

The months with the lowest UV index are January and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a low health risk from unsafe exposure to UV radiation for average individuals.
Note: The maximum daily UV index of 2 during December translates into the following directions:
Most people face no serious problems with extended sun exposure, but those with fair skin, infants, and children always need protection. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. To cut down UV radiation exposure by about half, sport a wide-brim hat. Bear in mind! The Sun's UV radiation can nearly double in intensity due to the reflective quality of snow.
Updated: Jul 16, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average December temperature?

In December, the average high-temperature and low-temperature are 45.5°F (7.5°C) and 34.3°F (1.3°C) respectively. In August, the average heat index (a.k.a. 'real feel', 'feels like'), which combines relative humidity and air temperature, is appraised at 93.2°F (34°C).

What are the most humid months?

May, October and December, with an average relative humidity of 76%, are most humid months.

What is the average humidity in December?

In December, the average relative humidity is 76%.

How many days does it rain in December?

In Riverdale Heights, during December, the rain falls for 9.8 days and regularly aggregates up to 2.6" (66mm) of precipitation.

When does it start snowing?

December is the first month it typically snows. Throughout December, in the average 2.4 snowfall days, it receives 0.67" (17mm) of snow.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 30min of daylight.

How many hours of daylight does Riverdale Heights have in December?

In December, the average day length is 9h and 29min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 7:08 am and sunset at 4:45 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 4:55 pm EST.

How many hours of sunshine does Riverdale Heights have in December?

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

What are the months with the lowest UV index?

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

What is the UV index reading in December?

In December, the average daily maximum UV index 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
Riverdale Heights, MD

Average temperature in December - Riverdale Heights, MD
  • Average high temperature in December: 45.5°F

The warmest month (with the highest average high temperature) is July (87.4°F).
The month with the lowest average high temperature is January (39.9°F).

  • Average low temperature in December: 34.3°F

The month with the highest average low temperature is July (70°F).
The coldest month (with the lowest average low temperature) is January (27.7°F).

Average pressure in December
Riverdale Heights, MD

Average pressure in December - Riverdale Heights, MD
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in December
Riverdale Heights, MD

Average wind speed in December - Riverdale Heights, MD
  • Average wind speed in December: 7.3mph

The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).

Average humidity in December
Riverdale Heights, MD

Average humidity in December - Riverdale Heights, MD
  • Average humidity in December: 76%

The months with the highest relative humidity are May, October and December (76%).
The months with the lowest relative humidity are April and July (71%).

Average rainfall in December
Riverdale Heights, MD

Average rainfall in December - Riverdale Heights, MD
  • Average rainfall in December: 2.6"

The wettest month (with the highest rainfall) is August (3.58").
The driest month (with the least rainfall) is January (2.01").

Average rainfall days in December
Riverdale Heights, MD

Average rainfall days in December - Riverdale Heights, MD
  • Average rainfall days in December: 9.8 days

The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is November (9 days).

Average snowfall in December
Riverdale Heights, MD

Average snowfall in December - Riverdale Heights, MD
  • Average snowfall in December: 0.67"

The month with the highest snowfall is January (2.6").
The months with the least snowfall are May, June, July, August, September, October and November (0").

Average snowfall days in December
Riverdale Heights, MD

Average snowfall days in December - Riverdale Heights, MD
  • Average snowfall days in December: 2.4 days

The month with the highest number of snowfall days is January (4.1 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight in December /
Average sunshine in December
Riverdale Heights, MD

Average daylight in December / Average sunshine in December - Riverdale Heights, MD
  • Average daylight in December: 9h and 3min

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in December: 5h and 1min

The month with the most sunshine is July (Average sunshine: 10h and 54min).
The month with the least sunshine is February (Average sunshine: 5h and 0min).

Average sunshine days in December
Riverdale Heights, MD

Average sunshine days in December - Riverdale Heights, MD
  • Average sunshine days in December: 18.1 days

The month with the most sunshine days is November (19.1 days).
The month with the least sunshine days is May (11.8 days).

Average UV index in December
Riverdale Heights, MD

Average UV index in December - Riverdale Heights, MD
  • 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 and December (UV index 2).

Average cloud cover in December
Riverdale Heights, MD

Average cloud cover in December - Riverdale Heights, MD
  • Average cloud cover in December: 45

The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 29).

Average visibility in December
Riverdale Heights, MD

Average visibility in December - Riverdale Heights, MD
  • 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).

Riverdale Heights, Maryland, USA

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