December weather forecastBlack Diamond, WA
December
Weather in December
December, the first month of the winter in Black Diamond, is still a cold month, with an average temperature ranging between max 40.8°F (4.9°C) and min 32°F (0°C).Temperature
December, characterized by an average high temperature of 40.8°F (4.9°C) and a low temperature of 32°F (0°C), is generally the coldest month.Humidity
In December, the average relative humidity is 85%.Rainfall
December is the month with the most rainfall in Black Diamond. Rain falls for 18.7 days and accumulates 5.43" (138mm) of precipitation.Snowfall
Months with snowfall in Black Diamond are January through April, November and December. In Black Diamond, in December, snow falls for 3.9 days, with typically accumulated 1.65" (42mm) of snow. In Black Diamond, during the entire year, snow falls for 19.7 days and aggregates up to 11.5" (292mm) of snow.Daylight
With an average of 8h and 30min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:35 am and sunset at 4:19 pm. On the last day of December, sunrise is at 7:54 am and sunset at 4:27 pm PST.
Sunshine
The months with the least sunshine are January and December, with an average of 4.1h of sunshine.UV index
The average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for the average person.Note: The maximum UV index of 2 during December leads to these instructions:
In contrast to children, who must always be shielded from the sun, most people can tolerate up to an hour of sun exposure without any burns. For skin protection, it's recommended to minimize Sun exposure during its peak hours around midday. To cut down UV radiation exposure by about half, sport a wide-brim hat. Forewarned is forearmed! The Sun's UV radiation can be almost doubled in intensity by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Black Diamond, WA
- Average high temperature in December: 40.8°F
The warmest month (with the highest average high temperature) is August (75.4°F).
The month with the lowest average high temperature is December (40.8°F).
- Average low temperature in December: 32°F
The month with the highest average low temperature is August (50.2°F).
The coldest month (with the lowest average low temperature) is February (31.6°F).
Average pressure in December
Black Diamond, WA
- Average pressure in December: 30.09"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The months with the lowest atmospheric pressure are August and September (30"Hg).
Average wind speed in December
Black Diamond, WA
- Average wind speed in December: 4.8mph
The windiest month (with the highest average wind speed) is January (5.2mph).
The calmest month (with the lowest average wind speed) is August (3.5mph).
Average humidity in December
Black Diamond, WA
- Average humidity in December: 85%
The months with the highest relative humidity are January and February (86%).
The month with the lowest relative humidity is July (70%).
Average rainfall in December
Black Diamond, WA
- Average rainfall in December: 5.43"
The wettest month (with the highest rainfall) is December (5.43").
The driest month (with the least rainfall) is July (0.59").
Average rainfall days in December
Black Diamond, WA
- Average rainfall days in December: 18.7 days
The month with the highest number of rainy days is March (20.5 days).
The month with the least rainy days is August (6.7 days).
Average snowfall in December
Black Diamond, WA
- Average snowfall in December: 1.65"
The month with the highest snowfall is February (4.17").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Black Diamond, WA
- Average snowfall days in December: 3.9 days
The month with the highest number of snowfall days is February (6 days).
The months with the least snowfall days are June, July, August and October (0 days).
Average daylight in December /
Average sunshine in December
Black Diamond, WA
- Average daylight in December: 8h and 30min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in December: 4h and 6min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The months with the least sunshine are January and December (Average sunshine: 4h and 6min).
Average sunshine days in December
Black Diamond, WA
- Average sunshine days in December: 10.3 days
The month with the most sunshine days is August (22 days).
The month with the least sunshine days is February (8.4 days).
Average UV index in December
Black Diamond, WA
- Average UV index in December: 2
The month with the highest UV index is July (UV index 5).
The month with the lowest UV index is November (UV index 1).
Average cloud cover in December
Black Diamond, WA
- Average cloud cover in December: 57
The months with the most cloud cover are January, February, March and December (Cloud cover 57).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in December
Black Diamond, WA
- Average visibility in December: 4mi
The months with the highest visibility are July and August (6mi).
The months with the lowest visibility are January, February and December (4mi).
