December weather forecastCastle Rock, WA
December
Weather in December
The first month of the winter, December, is also a wintry month in Castle Rock, Washington, with an average temperature ranging between min 32.5°F (0.3°C) and max 42.4°F (5.8°C).Temperature
The coldest period is December, when temperatures fluctuate between an average high of 42.4°F (5.8°C) and a low of 32.5°F (0.3°C).Humidity
The average relative humidity in December in Castle Rock is 88%.Rainfall
In Castle Rock, Washington, during December, the rain falls for 15.4 days and regularly aggregates up to 2.13" (54mm) of precipitation. Throughout the year, in Castle Rock, there are 157.3 rainfall days, and 16.54" (420mm) of precipitation is accumulated.Snowfall
January through March, November and December are months with snowfall in Castle Rock, Washington. In Castle Rock, Washington, in December, during 0.9 snowfall days, 0.2" (5mm) of snow is typically accumulated. Throughout the year, in Castle Rock, there are 7 snowfall days, and 2.99" (76mm) of snow is accumulated.Daylight
The month with the shortest days in Castle Rock is December, with an average of 8h and 42min of daylight.On the first day of December, sunrise is at 7:34 am and sunset at 4:27 pm. On the last day of the month, sunrise is at 7:54 am and sunset at 4:35 pm PST.
Sunshine
In December, the average sunshine in Castle Rock is 3.6h.UV index
The months with the lowest UV index in Castle Rock, Washington, are January, February, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: A maximum high UV index of 2 in December translates into the following recommendations:
Unlike children, who always need sun protection, most individuals can remain in the sun for up to an hour without getting burnt. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. During bright days, sunglasses that offer UVA and UVB defense are recommended. Consider carefully! The reflective quality of snow can almost double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Castle Rock, WA
- Average high temperature in December: 42.4°F
The warmest month (with the highest average high temperature) is August (77.7°F).
The month with the lowest average high temperature is December (42.4°F).
- Average low temperature in December: 32.5°F
The month with the highest average low temperature is August (49.6°F).
The coldest month (with the lowest average low temperature) is December (32.5°F).
Average pressure in December
Castle Rock, WA
- Average pressure in December: 30.09"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).
Average wind speed in December
Castle Rock, WA
- Average wind speed in December: 4.5mph
The windiest month (with the highest average wind speed) is January (4.8mph).
The calmest months (with the lowest average wind speed) are August and September (3.7mph).
Average humidity in December
Castle Rock, WA
- Average humidity in December: 88%
The months with the highest relative humidity are February and November (89%).
The months with the lowest relative humidity are July and August (73%).
Average rainfall in December
Castle Rock, WA
- Average rainfall in December: 2.13"
The wettest month (with the highest rainfall) is January (2.28").
The driest month (with the least rainfall) is August (0.31").
Average rainfall days in December
Castle Rock, WA
- Average rainfall days in December: 15.4 days
The month with the highest number of rainy days is March (17.5 days).
The month with the least rainy days is July (6.1 days).
Average snowfall in December
Castle Rock, WA
- Average snowfall in December: 0.2"
The month with the highest snowfall is February (1.02").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in December
Castle Rock, WA
- Average snowfall days in December: 0.9 days
The month with the highest number of snowfall days is February (2.4 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
Castle Rock, WA
- Average daylight in December: 8h and 42min
The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).
- Average sunshine in December: 3h and 36min
The month with the most sunshine is August (Average sunshine: 10h and 18min).
The month with the least sunshine is February (Average sunshine: 3h and 30min).
Average sunshine days in December
Castle Rock, WA
- Average sunshine days in December: 12.5 days
The month with the most sunshine days is August (21.9 days).
The month with the least sunshine days is April (10.5 days).
Average UV index in December
Castle Rock, WA
- Average UV index in December: 2
The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Castle Rock, WA
- Average cloud cover in December: 63
The month with the most cloud cover is February (Cloud cover 65).
The month with the least cloud cover is August (Cloud cover 37).
Average visibility in December
Castle Rock, WA
- Average visibility in December: 4mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (4mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (4mi).
