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, with average temperatures reaching a high of 41.5°F (5.3°C) and a low of 32.9°F (0.5°C), is the coldest month.Humidity
November and December, with an average relative humidity of 90%, are the most humid months in Union, Washington.Rainfall
In Union, in December, it is raining for 19.9 days, with typically 7.17" (182mm) of accumulated precipitation. In Union, during the entire year, the rain falls for 185.4 days and collects up to 42.87" (1089mm) of precipitation.Snowfall
Months with snowfall in Union are January through March, November and December. In Union, during December, snow falls for 1.6 days and regularly aggregates up to 0.71" (18mm) of snow. Throughout the year, in Union, there are 9.1 snowfall days, and 5.59" (142mm) of snow is accumulated.Daylight
December has the shortest days of the year in Union, with an average of 8h and 30min of daylight.On the first day of the month, sunrise is at 7:39 am and sunset at 4:23 pm. On the last day of December, in Union, sunrise is at 7:59 am and sunset at 4:32 pm PST.
Sunshine
December has the least sunshine of the year, with an average of 3.5h of sunshine.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a low threat to health from exposure to the Sun's UV radiation for average individuals.Note: In December, the average maximum UV index of 2 translates into the following recommendations:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Pay attention! The reflection of snow can enhance the Sun's UV radiation almost double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What month is the coldest in Union?
How cold does it get in Union in December?
What are the most humid months in Union?
What is the average humidity in December in Union?
How much does it rain in Union in December?
How much does it snow in Union in December?
What is the month with the shortest days in Union?
What is the average length of the day in December in Union?
What time are sunrise and sunset in December in Union?
What is the month with the least sunshine in Union?
How long on average sun shines in December in Union?
What are the months with the lowest UV index in Union?
What is the UV index reading in December in Union?
Average temperature in December
Union, WA
- Average high temperature in December: 41.5°F
The warmest month (with the highest average high temperature) is August (76.6°F).
The month with the lowest average high temperature is December (41.5°F).
- Average low temperature in December: 32.9°F
The month with the highest average low temperature is August (50.4°F).
The coldest month (with the lowest average low temperature) is February (32.7°F).
Average pressure in December
Union, WA
- Average pressure in December: 30.06"Hg
The month with the highest atmospheric pressure is January (30.08"Hg).
The month with the lowest atmospheric pressure is March (30.01"Hg).
Average wind speed in December
Union, WA
- Average wind speed in December: 3.7mph
The windiest month (with the highest average wind speed) is March (4.3mph).
The calmest month (with the lowest average wind speed) is September (3.4mph).
Average humidity in December
Union, WA
- Average humidity in December: 90%
The months with the highest relative humidity are November and December (90%).
The month with the lowest relative humidity is July (72%).
Average rainfall in December
Union, WA
- Average rainfall in December: 7.17"
The wettest month (with the highest rainfall) is January (7.24").
The driest month (with the least rainfall) is July (0.43").
Average rainfall days in December
Union, WA
- Average rainfall days in December: 19.9 days
The month with the highest number of rainy days is March (21.4 days).
The month with the least rainy days is August (6.3 days).
Average snowfall in December
Union, WA
- Average snowfall in December: 0.71"
The month with the highest snowfall is February (2.17").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in December
Union, WA
- Average snowfall days in December: 1.6 days
The month with the highest number of snowfall days is February (3.3 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
Union, WA
- Average daylight in December: 8h and 3min
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: 3h and 3min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 3h and 30min).
Average sunshine days in December
Union, WA
- Average sunshine days in December: 9.4 days
The month with the most sunshine days is July (21.7 days).
The month with the least sunshine days is March (7.5 days).
Average UV index in December
Union, 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
Union, WA
- Average cloud cover in December: 64
The months with the most cloud cover are January and December (Cloud cover 64).
The months with the least cloud cover are July and August (Cloud cover 30).
Average visibility in December
Union, WA
- Average visibility in December: 4mi
The months with the highest visibility are June, July, August and September (5mi).
The months with the lowest visibility are January, February, March, April, May, October, November and December (4mi).
Union, Washington, USA
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