December weather forecastWashington, CA
December
Weather in December
December, the first month of the winter in Washington, is still a chilly month, with an average temperature varying between 43.7°F (6.5°C) and 29.1°F (-1.6°C).Temperature
Washington's temperature records reveal December as the coldest month, marked by average highs of 43.7°F (6.5°C) and lows of 29.1°F (-1.6°C).Humidity
The average relative humidity in December is 72%.Rainfall
In Washington, during December, the rain falls for 7.5 days and regularly aggregates up to 5.55" (141mm) of precipitation. In Washington, California, during the entire year, the rain falls for 72.9 days and collects up to 36.06" (916mm) of precipitation.Snowfall
Months with snowfall are January through June, September through December. In December, in Washington, California, it is snowing for 9 days. Throughout December, 21.69" (551mm) of snow is accumulated. Throughout the year, in Washington, there are 53.3 snowfall days, and 151.57" (3850mm) of snow is accumulated.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:04 am and sunset at 4:40 pm. On the last day of December, in Washington, sunrise is at 7:23 am and sunset at 4:50 pm PST.
Sunshine
In Washington, the average sunshine in December is 5.7h.UV index
The months with the lowest UV index in Washington are January through March, November and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for the average person.Note: The daily high UV index of 2 during December translates into the following recommendations:
Although the majority can endure up to an hour in the sun without burns, children always require sun protection. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim. Take warning! The intensity of the Sun's UV radiation can be nearly amplified twice due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Washington, CA
- Average high temperature in December: 43.7°F
The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is December (43.7°F).
- Average low temperature in December: 29.1°F
The month with the highest average low temperature is July (52.9°F).
The coldest month (with the lowest average low temperature) is December (29.1°F).
Average pressure in December
Washington, CA
- Average pressure in December: 30.14"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in December
Washington, CA
- Average wind speed in December: 5.8mph
The windiest month (with the highest average wind speed) is February (6.3mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).
Average humidity in December
Washington, CA
- Average humidity in December: 72%
The month with the highest relative humidity is March (80%).
The month with the lowest relative humidity is July (39%).
Average rainfall in December
Washington, CA
- Average rainfall in December: 5.55"
The wettest month (with the highest rainfall) is March (7.09").
The driest month (with the least rainfall) is July (0.08").
Average rainfall days in December
Washington, CA
- Average rainfall days in December: 7.5 days
The month with the highest number of rainy days is April (11 days).
The month with the least rainy days is July (1.8 days).
Average snowfall in December
Washington, CA
- Average snowfall in December: 21.69"
The month with the highest snowfall is March (37.6").
The months with the least snowfall are July and August (0").
Average snowfall days in December
Washington, CA
- Average snowfall days in December: 9 days
The month with the highest number of snowfall days is March (11.7 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in December /
Average sunshine in December
Washington, CA
- Average daylight in December: 9h and 24min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in December: 5h and 42min
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 36min).
Average sunshine days in December
Washington, CA
- Average sunshine days in December: 17.6 days
The month with the most sunshine days is July (28 days).
The month with the least sunshine days is March (12.6 days).
Average UV index in December
Washington, CA
- Average UV index in December: 2
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in December
Washington, CA
- Average cloud cover in December: 36
The month with the most cloud cover is March (Cloud cover 45).
The month with the least cloud cover is July (Cloud cover 5).
Average visibility in December
Washington, CA
- Average visibility in December: 6mi
The months with the highest visibility are May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March and April (5mi).





