Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
The start of December involves a subtle temperature drop, shifting from a fresh 54.9°F (12.7°C) in November to a frosty 46.6°F (8.1°C). The low-temperature averages to a wintry 33.6°F (0.9°C) during the nights of December.Humidity
The months with the highest humidity are May, October and December, with an average relative humidity of 77%.Rainfall
In Potomac Heights, in December, it is raining for 10.7 days, with typically 2.68" (68mm) of accumulated precipitation. In Potomac Heights, during the entire year, the rain falls for 164.3 days and collects up to 32.32" (821mm) of precipitation.Snowfall
Months with snowfall are January through April and December. December is the first month it typically snows. Throughout December, in the average 2.1 snowfall days, it receives 1.42" (36mm) of snow. In Potomac Heights, during the entire year, snow falls for 14.6 days and aggregates up to 7.8" (198mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 30min of daylight.On the first day of December, sunrise is at 7:07 am and sunset at 4:47 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 4:57 pm EST.
Sunshine
The months with the least sunshine are February and December, with an average of 5.2h of sunshine.UV index
The months with the lowest UV index are January, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV rays for average individuals.Note: The maximum UV index of 2 during December translates into these guidelines:
Prolonged exposure to sunlight rarely troubles the majority, but constant protection is vital for babies, children, and fair-skinned people. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in December?
What are the most humid months?
What is the average humidity in December?
How many days does it rain in December?
When does it start to snow?
What is the month with the shortest days?
What is the average length of the day in December?
What time are sunrise and sunset in December?
What is the month with the least sunshine in Potomac Heights?
How long on average sun shines in December?
What is the month with the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Potomac Heights, MD
- Average high temperature in December: 46.6°F
The warmest month (with the highest average high temperature) is July (88.2°F).
The month with the lowest average high temperature is January (41°F).
- Average low temperature in December: 33.6°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (27.3°F).
Average pressure in December
Potomac 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 (29.95"Hg).
Average wind speed in December
Potomac Heights, MD
- Average wind speed in December: 6.2mph
The windiest months (with the highest average wind speed) are March and April (7.3mph).
The calmest months (with the lowest average wind speed) are July and August (4.8mph).
Average humidity in December
Potomac Heights, MD
- Average humidity in December: 77%
The months with the highest relative humidity are May, October and December (77%).
The months with the lowest relative humidity are April and July (72%).
Average rainfall in December
Potomac Heights, MD
- Average rainfall in December: 2.68"
The wettest month (with the highest rainfall) is August (3.86").
The driest month (with the least rainfall) is January (2.01").
Average rainfall days in December
Potomac Heights, MD
- Average rainfall days in December: 10.7 days
The month with the highest number of rainy days is May (18.1 days).
The month with the least rainy days is November (9.1 days).
Average snowfall in December
Potomac Heights, MD
- Average snowfall in December: 1.42"
The month with the highest snowfall is January (2.44").
The months with the least snowfall are May, June, July, August, September, October and November (0").
Average snowfall days in December
Potomac Heights, MD
- Average snowfall days in December: 2.1 days
The month with the highest number of snowfall days is January (4.8 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
Potomac Heights, MD
- Average daylight in December: 9h and 3min
The month with the longest days is June (Average daylight: 14h and 48min).
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 48min).
The months with the least sunshine are February and December (Average sunshine: 5h and 12min).
Average sunshine days in December
Potomac Heights, MD
- Average sunshine days in December: 17.5 days
The month with the most sunshine days is November (19.3 days).
The month with the least sunshine days is May (10.6 days).
Average UV index in December
Potomac 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, November and December (UV index 2).
Average cloud cover in December
Potomac Heights, MD
- Average cloud cover in December: 44
The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 30).
Average visibility in December
Potomac Heights, MD
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).
Potomac Heights, Maryland, USA
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