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 sea temperature 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
Charlestown experiences a moderate temperature shift at the start of December, with average high-temperatures adjusting a bit from a fresh 53.1°F (11.7°C) in November to a chilly 44.1°F (6.7°C). During December, an average low-temperature of 33.1°F (0.6°C) is observed.Humidity
The average relative humidity in December is 77%.Rainfall
In December, the rain falls for 9.8 days. Throughout December, 2.4" (61mm) of precipitation is accumulated. Throughout the year, in Charlestown, there are 150.3 rainfall days, and 29.25" (743mm) of precipitation is accumulated.Snowfall
January through March, May, November and December are months with snowfall. In Charlestown, in December, during 1.7 snowfall days, 0.83" (21mm) of snow is typically accumulated. In Charlestown, during the entire year, snow falls for 13.1 days and aggregates up to 6.89" (175mm) of snow.Ocean temperature
In December, the average ocean temperature is 48.6°F (9.2°C).Note: Diving into 48.6°F (9.2°C) is practical below 50°F (10°C), given you're wearing protective swim gear; without it, expect a quick onset of cold shock and a struggle to breathe. Merely touching waters at 55.4°F (13°C) feels ice-cold.
Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year in Charlestown.On the first day of the month, sunrise is at 7:05 am and sunset at 4:40 pm. On the last day of December, sunrise is at 7:24 am and sunset at 4:50 pm EST.
Sunshine
The average sunshine in December is 5.1h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a minimal health hazard from unsafe exposure to UV radiation for the average person.Note: In December, an average UV index of 2 transforms into the following instructions:
Extended sunlight exposure does not pose significant problems for most people, except for children, infants, and people with fair skin who always need shielding. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage. Note this! The Sun's UV radiation can nearly be doubled by the reflection off snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What is the average humidity in December?
How much does it rain in December?
How many days does it snow in December in Charlestown?
What is the water temperature in December?
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?
How many hours of sunshine does Charlestown have in December?
What are the months with the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Charlestown, MD
- Average high temperature in December: 44.1°F
The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (37.9°F).
- Average low temperature in December: 33.1°F
The month with the highest average low temperature is July (67.6°F).
The coldest month (with the lowest average low temperature) is January (26.1°F).
Average pressure in December
Charlestown, MD
- 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 (29.94"Hg).
Average wind speed in December
Charlestown, MD
- Average wind speed in December: 8.1mph
The windiest months (with the highest average wind speed) are February and March (8.9mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).
Average humidity in December
Charlestown, MD
- Average humidity in December: 77%
The months with the highest relative humidity are May and June (79%).
The month with the lowest relative humidity is April (74%).
Average rainfall in December
Charlestown, MD
- Average rainfall in December: 2.4"
The wettest month (with the highest rainfall) is August (3.86").
The driest month (with the least rainfall) is January (1.85").
Average rainfall days in December
Charlestown, MD
- Average rainfall days in December: 9.8 days
The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (7.8 days).
Average snowfall in December
Charlestown, MD
- Average snowfall in December: 0.83"
The month with the highest snowfall is January (2.24").
The months with the least snowfall are April, June, July, August, September and October (0").
Average snowfall days in December
Charlestown, MD
- Average snowfall days in December: 1.7 days
The month with the highest number of snowfall days is January (4.4 days).
The months with the least snowfall days are April, June, July, August, September and October (0 days).
Average sea temperature in December
Charlestown, MD
- Average sea temperature in December: 48.5°F
The best month for swimming (with the highest average sea temperature) is August (76.3°F).
The coldest month (with the lowest average sea temperature) is February (40.9°F).
Average daylight in December /
Average sunshine in December
Charlestown, MD
- Average daylight in December: 9h and 2min
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 24min).
- Average sunshine in December: 5h and 1min
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).
Average sunshine days in December
Charlestown, MD
- Average sunshine days in December: 18.9 days
The month with the most sunshine days is November (20.4 days).
The month with the least sunshine days is July (11.6 days).
Average UV index in December
Charlestown, 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, February, November and December (UV index 2).
Average cloud cover in December
Charlestown, MD
- Average cloud cover in December: 45
The months with the most cloud cover are February and March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in December
Charlestown, MD
- 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).
Charlestown, Maryland, USA
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