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
December, having an average high-temperature of 38.1°F (3.4°C) and an average low-temperature of 27.5°F (-2.5°C), is the coldest month.Humidity
The average relative humidity in December is 78%.Rainfall
The month with the most rainfall is December, when the rain falls for 10.3 days and typically aggregates up to 0.94" (24mm) of precipitation.Snowfall
Months with snowfall are January through March, November and December. In December, it is snowing for 3.3 days. Throughout December, 1.5" (38mm) of snow is accumulated. In Richland, Washington, during the entire year, snow falls for 10.4 days and aggregates up to 5.35" (136mm) of snow.Daylight
With an average of 8h and 42min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:20 am and sunset at 4:12 pm. On the last day of the month, sunrise is at 7:40 am and sunset at 4:20 pm PST.
Sunshine
In Richland, the average sunshine in December is 5.6h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Richland. A UV Index reading of 2, and below, represents a low threat to health from exposure to the Sun's UV rays for the average person.Note: The maximum daily UV index of 2 in December converts into the following recommendations:
Most people face no serious problems with extended sun exposure, but those with fair skin, infants, and children always need protection. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Bear in mind! The Sun's UV radiation can nearly double in intensity due to the reflective quality of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What time of the year is the coldest?
How cold is it in December?
What is the average humidity in December?
What is the wettest month?
How many days does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Richland have in December?
When are sunrise and sunset in December?
How many hours of sunshine does Richland have in December?
What is the month with the lowest UV index?
How high is the UV index in December?
Average temperature in December
Richland, WA
- Average high temperature in December: 38.1°F
The warmest month (with the highest average high temperature) is July (90.1°F).
The month with the lowest average high temperature is December (38.1°F).
- Average low temperature in December: 27.5°F
The month with the highest average low temperature is August (64.2°F).
The coldest month (with the lowest average low temperature) is December (27.5°F).
Average pressure in December
Richland, WA
- Average pressure in December: 30.16"Hg
The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in December
Richland, WA
- Average wind speed in December: 5.6mph
The windiest month (with the highest average wind speed) is April (8.3mph).
The calmest month (with the lowest average wind speed) is December (5.6mph).
Average humidity in December
Richland, WA
- Average humidity in December: 78%
The month with the highest relative humidity is January (81%).
The month with the lowest relative humidity is July (35%).
Average rainfall in December
Richland, WA
- Average rainfall in December: 0.94"
The wettest month (with the highest rainfall) is December (0.94").
The driest months (with the least rainfall) are July and September (0.2").
Average rainfall days in December
Richland, WA
- Average rainfall days in December: 10.3 days
The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is July (3.5 days).
Average snowfall in December
Richland, WA
- Average snowfall in December: 1.5"
The month with the highest snowfall is February (2.2").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in December
Richland, WA
- Average snowfall days in December: 3.3 days
The month with the highest number of snowfall days is December (3.3 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Richland, WA
- Average daylight in December: 8h and 4min
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: 5h and 4min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 5h and 24min).
Average sunshine days in December
Richland, WA
- Average sunshine days in December: 16.6 days
The month with the most sunshine days is July (25.7 days).
The months with the least sunshine days are February and March (15.3 days).
Average UV index in December
Richland, WA
- Average UV index in December: 2
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Richland, WA
- Average cloud cover in December: 42
The month with the most cloud cover is January (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility in December
Richland, WA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Richland, Washington, USA
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