December weather forecastCopalis Beach, WA
December
Weather in December
December, the first month of the winter in Copalis Beach, is also a frosty month, with temperature in the range of an average high of 45.5°F (7.5°C) and an average low of 39.7°F (4.3°C).Temperature
During the coldest month, December, temperatures average a high of 45.5°F (7.5°C) and a low of 39.7°F (4.3°C).Humidity
December is the most humid month, with an average relative humidity of 85%.Rainfall
December is the month with the most rainfall. Rain falls for 18.5 days and accumulates 3.35" (85mm) of precipitation.Snowfall
In Copalis Beach, snow does not fall in April through October and December.Daylight
December has the shortest days of the year, with an average of 8h and 36min of daylight.On the first day of the month, sunrise is at 7:43 am and sunset at 4:29 pm. On the last day of December, sunrise is at 8:02 am and sunset at 4:37 pm PST.
Sunshine
In December, the average sunshine is 3.6h.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 minimal health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: A typical high UV index of 2 in December suggests the following recommendations:
Most individuals face no major issues with lengthy exposure to the sun, but children, infants, and individuals with fair skin always require protection. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Be alert! Nearly double the UV rays from the Sun can be reflected by snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Copalis Beach, WA
- Average high temperature in December: 45.5°F
The warmest month (with the highest average high temperature) is August (65.8°F).
The month with the lowest average high temperature is December (45.5°F).
- Average low temperature in December: 39.7°F
The month with the highest average low temperature is August (54.5°F).
The coldest month (with the lowest average low temperature) is December (39.7°F).
Average pressure in December
Copalis Beach, WA
- Average pressure in December: 30.04"Hg
The month with the highest atmospheric pressure is July (30.08"Hg).
The month with the lowest atmospheric pressure is March (30"Hg).
Average wind speed in December
Copalis Beach, WA
- Average wind speed in December: 10.1mph
The windiest month (with the highest average wind speed) is January (10.9mph).
The calmest month (with the lowest average wind speed) is September (7.1mph).
Average humidity in December
Copalis Beach, WA
- Average humidity in December: 85%
The month with the highest relative humidity is December (85%).
The months with the lowest relative humidity are April, May and June (81%).
Average rainfall in December
Copalis Beach, WA
- Average rainfall in December: 3.35"
The wettest month (with the highest rainfall) is December (3.35").
The driest month (with the least rainfall) is July (0.24").
Average rainfall days in December
Copalis Beach, WA
- Average rainfall days in December: 18.5 days
The month with the highest number of rainy days is December (18.5 days).
The month with the least rainy days is July (5.6 days).
Average snowfall in December
Copalis Beach, WA
- Average snowfall in December: 0"
The month with the highest snowfall is February (1.02").
The months with the least snowfall are April, May, June, July, August, September, October and December (0").
Average snowfall days in December
Copalis Beach, WA
- Average snowfall days in December: 0.3 days
The month with the highest number of snowfall days is February (1.6 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
Copalis Beach, WA
- Average daylight in December: 8h and 36min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in December: 3h and 36min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in December
Copalis Beach, WA
- Average sunshine days in December: 10.7 days
The month with the most sunshine days is July (23.8 days).
The month with the least sunshine days is December (10.7 days).
Average UV index in December
Copalis Beach, WA
- Average UV index in December: 2
The months with the highest UV index are May, June, July, August and September (UV index 4).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Copalis Beach, WA
- Average cloud cover in December: 61
The month with the most cloud cover is January (Cloud cover 63).
The month with the least cloud cover is July (Cloud cover 33).
Average visibility in December
Copalis Beach, WA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, September, October, November and December (6mi).
The month with the lowest visibility is August (5mi).





