December weather forecastArlington, WA

December
Weather in December
December, the first month of the winter in Arlington, is also a wintry month, with temperature in the range of an average high of 41.7°F (5.4°C) and an average low of 34°F (1.1°C).Temperature
Arlington, Washington, notes the coldest temperatures in December, with a high average of 41.7°F (5.4°C) and a low of 34°F (1.1°C).Humidity
January, February, November and December, with an average relative humidity of 85%, are the most humid months.Rainfall
In Arlington, in December, during 19.4 rainfall days, 4.53" (115mm) of precipitation is typically accumulated. Throughout the year, there are 188.6 rainfall days, and 34.92" (887mm) of precipitation is accumulated.Snowfall
January through April, November and December are months with snowfall. In December, it is snowing for 2 days. Throughout December, 0.67" (17mm) of snow is accumulated. In Arlington, during the entire year, snow falls for 11.6 days and aggregates up to 9.61" (244mm) of snow.Daylight
With an average of 8h and 24min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:38 am and sunset at 4:16 pm. On the last day of the month, sunrise is at 7:59 am and sunset at 4:24 pm PST.
Sunshine
December has the least sunshine of the year, with an average of 4.1h of sunshine.UV index
January, February, October through December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The UV index of 2 in December translates into these instructions:
Most individuals face no significant issues with extended sun exposure, but it is always essential to protect children, babies, and those with sensitive skin. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Arlington, WA
- Average high temperature in December: 41.7°F
The warmest month (with the highest average high temperature) is August (72.3°F).
The month with the lowest average high temperature is December (41.7°F).
- Average low temperature in December: 34°F
The month with the highest average low temperature is August (51.6°F).
The coldest month (with the lowest average low temperature) is February (33.8°F).
Average pressure in December
Arlington, WA
- Average pressure in December: 30.08"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).
Average wind speed in December
Arlington, WA
- Average wind speed in December: 5.3mph
The windiest months (with the highest average wind speed) are January and November (5.6mph).
The calmest month (with the lowest average wind speed) is August (3.3mph).
Average humidity in December
Arlington, WA
- Average humidity in December: 85%
The months with the highest relative humidity are January, February, November and December (85%).
The month with the lowest relative humidity is July (73%).
Average rainfall in December
Arlington, WA
- Average rainfall in December: 4.53"
The wettest month (with the highest rainfall) is November (4.92").
The driest month (with the least rainfall) is July (0.51").
Average rainfall days in December
Arlington, WA
- Average rainfall days in December: 19.4 days
The month with the highest number of rainy days is March (20.9 days).
The month with the least rainy days is August (6.9 days).
Average snowfall in December
Arlington, WA
- Average snowfall in December: 0.67"
The month with the highest snowfall is February (4.45").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Arlington, WA
- Average snowfall days in December: 2 days
The month with the highest number of snowfall days is February (4.3 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
Arlington, WA
- Average daylight in December: 8h and 24min
The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 24min).
- Average sunshine in December: 4h and 6min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 6min).
Average sunshine days in December
Arlington, WA
- Average sunshine days in December: 9.5 days
The month with the most sunshine days is August (22 days).
The month with the least sunshine days is March (8.1 days).
Average UV index in December
Arlington, WA
- Average UV index in December: 2
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in December
Arlington, WA
- Average cloud cover in December: 57
The month with the most cloud cover is December (Cloud cover 57).
The months with the least cloud cover are July and August (Cloud cover 26).
Average visibility in December
Arlington, WA
- Average visibility in December: 5mi
The months with the highest visibility are March, April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, November and December (5mi).





