December weather forecastValley, WA
December
Weather in December
The first month of the winter, December, is also a subzero cold month in Valley, Washington, with an average temperature fluctuating between 18.7°F (-7.4°C) and 29.8°F (-1.2°C).Temperature
December, characterized by an average high temperature of 29.8°F (-1.2°C) and a low temperature of 18.7°F (-7.4°C), is generally the coldest month.Humidity
The average relative humidity in December in Valley is 90%.Rainfall
In December, in Valley, the rain falls for 11.6 days. Throughout December, 2.05" (52mm) of precipitation is accumulated. Throughout the year, there are 141.6 rainfall days, and 17.56" (446mm) of precipitation is accumulated.Snowfall
January through April, September through December are months with snowfall in Valley, Washington. In Valley, Washington, in December, during 15.4 snowfall days, 8.19" (208mm) of snow is typically accumulated. In Valley, during the entire year, snow falls for 57.8 days and aggregates up to 34.09" (866mm) 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 in Valley, Washington, sunrise is at 7:21 am and sunset at 3:59 pm. On the last day of the month, sunrise is at 7:41 am and sunset at 4:07 pm PST.
Sunshine
In Valley, the average sunshine in December is 3.9h.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for the average person.Note: The maximum UV index of 1 during December leads to these instructions:
While sun exposure does not greatly affect most, individuals with fair skin, babies, and children always need vigilant safeguarding. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage. Mind you! Snow reflection can increase the intensity of the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Valley, WA
- Average high temperature in December: 29.8°F
The warmest month (with the highest average high temperature) is August (83.1°F).
The month with the lowest average high temperature is December (29.8°F).
- Average low temperature in December: 18.7°F
The month with the highest average low temperature is August (51.8°F).
The coldest month (with the lowest average low temperature) is December (18.7°F).
Average pressure in December
Valley, WA
- Average pressure in December: 30.17"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The months with the lowest atmospheric pressure are June and August (29.91"Hg).
Average wind speed in December
Valley, WA
- Average wind speed in December: 3.5mph
The windiest month (with the highest average wind speed) is April (4.7mph).
The calmest months (with the lowest average wind speed) are January and December (3.5mph).
Average humidity in December
Valley, WA
- Average humidity in December: 90%
The month with the highest relative humidity is January (94%).
The month with the lowest relative humidity is August (47%).
Average rainfall in December
Valley, WA
- Average rainfall in December: 2.05"
The wettest month (with the highest rainfall) is January (2.2").
The driest month (with the least rainfall) is August (0.35").
Average rainfall days in December
Valley, WA
- Average rainfall days in December: 11.6 days
The month with the highest number of rainy days is March (17.1 days).
The month with the least rainy days is August (5.6 days).
Average snowfall in December
Valley, WA
- Average snowfall in December: 8.19"
The month with the highest snowfall is January (10.47").
The months with the least snowfall are May, June, July and August (0").
Average snowfall days in December
Valley, WA
- Average snowfall days in December: 15.4 days
The month with the highest number of snowfall days is December (15.4 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in December /
Average sunshine in December
Valley, 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: 3h and 54min
The month with the most sunshine is August (Average sunshine: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in December
Valley, WA
- Average sunshine days in December: 12 days
The month with the most sunshine days is August (22.9 days).
The month with the least sunshine days is March (9.3 days).
Average UV index in December
Valley, WA
- Average UV index in December: 1
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover in December
Valley, WA
- Average cloud cover in December: 60
The month with the most cloud cover is January (Cloud cover 63).
The month with the least cloud cover is August (Cloud cover 13).
Average visibility in December
Valley, WA
- Average visibility in December: 4mi
The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January and February (3mi).
