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
With December's onset, the weather shows a temperature decrease, transitioning from a chilly 48.4°F (9.1°C) in November to an icy 39°F (3.9°C). During the month of December, an average low-temperature of 27.5°F (-2.5°C) is recorded.Humidity
In Port Royal, the average relative humidity in December is 81%.Rainfall
In Port Royal, in December, during 10.5 rainfall days, 2.17" (55mm) of precipitation is typically accumulated. In Port Royal, during the entire year, the rain falls for 162 days and collects up to 28.86" (733mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. In Port Royal, during December, snow falls for 6 days and regularly aggregates up to 2.76" (70mm) of snow. Throughout the year, there are 35.2 snowfall days, and 16.42" (417mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 18min of daylight.On the first day of December, sunrise is at 7:14 am and sunset at 4:43 pm. On the last day of the month, sunrise is at 7:32 am and sunset at 4:52 pm EST.
Sunshine
The average sunshine in December is 4.1h.UV index
January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: A daily maximum UV index of 2 in December translates into the following instructions:
While most people can stay under the sun for an hour without burning, children must always be guarded against sun exposure. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Guard yourself! Snow reflection can almost double the UV radiation from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold does it get in December?
What is the average humidity in December?
How many days does it rain in December?
How much does it snow in Port Royal 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 long on average sun shines in December in Port Royal?
What are the months with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Port Royal, PA
- Average high temperature in December: 39°F
The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (32.9°F).
- Average low temperature in December: 27.5°F
The month with the highest average low temperature is July (60.8°F).
The coldest month (with the lowest average low temperature) is January (19.9°F).
Average pressure in December
Port Royal, PA
- 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 (29.95"Hg).
Average wind speed in December
Port Royal, PA
- Average wind speed in December: 7mph
The windiest month (with the highest average wind speed) is January (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.4mph).
Average humidity in December
Port Royal, PA
- Average humidity in December: 81%
The month with the highest relative humidity is February (82%).
The month with the lowest relative humidity is July (75%).
Average rainfall in December
Port Royal, PA
- Average rainfall in December: 2.17"
The wettest month (with the highest rainfall) is May (3.31").
The driest months (with the least rainfall) are January and November (1.85").
Average rainfall days in December
Port Royal, PA
- Average rainfall days in December: 10.5 days
The month with the highest number of rainy days is May (19.1 days).
The month with the least rainy days is February (8.8 days).
Average snowfall in December
Port Royal, PA
- Average snowfall in December: 2.76"
The month with the highest snowfall is January (4.49").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Port Royal, PA
- Average snowfall days in December: 6 days
The month with the highest number of snowfall days is January (10.9 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Port Royal, 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 18min).
- Average sunshine in December: 4h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in December
Port Royal, PA
- Average sunshine days in December: 16.6 days
The month with the most sunshine days is November (19.4 days).
The month with the least sunshine days is May (10.4 days).
Average UV index in December
Port Royal, PA
- Average UV index in December: 2
The month with the highest UV index is June (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
Port Royal, PA
- Average cloud cover in December: 56
The month with the most cloud cover is January (Cloud cover 57).
The month with the least cloud cover is July (Cloud cover 34).
Average visibility in December
Port Royal, PA
- Average visibility in December: 5mi
The month with the highest visibility is April (6mi).
The months with the lowest visibility are January, February, March, May, June, July, August, September, October, November and December (5mi).
Port Royal, Pennsylvania, USA
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