December weather forecast
Copalis Crossing, WA

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Weather in December

The first month of the winter, December, is also a frosty month in Copalis Crossing, Washington, with an average temperature ranging between min 39.7°F (4.3°C) and max 45.5°F (7.5°C).

Temperature

Copalis Crossing's coldest month, December, generally records average temperatures ranging from a high of 45.5°F (7.5°C) to a low of 39.7°F (4.3°C).

Humidity

The most humid month is December, 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 Crossing, 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 7:42 am and sunset at 4:28 pm. On the last day of December, in Copalis Crossing, sunrise is at 8:02 am and sunset at 4:36 pm PST.

Sunshine

In Copalis Crossing, the average sunshine in December 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 estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for ordinary individuals.
Note: A maximum UV index of 2 in 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. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Be alert to the fact! The reflection from snow can nearly double the UV radiation of the Sun.
Updated: Jun 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What month is the coldest in Copalis Crossing?

Copalis Crossing records the coldest temperatures in December, averaging a high of 45.5°F (7.5°C) and a low of 39.7°F (4.3°C).

What are December temperatures?

December temperatures vary between a high-temperature of 45.5°F (7.5°C) and a low-temperature of 39.7°F (4.3°C).

What is the most humid month?

With an average relative humidity of 85%, December is the most humid month.

What is the average humidity in December?

In Copalis Crossing, Washington, the average relative humidity in December is 85%.

What is the wettest month?

December is the month with the most rainfall. Rain falls for 18.5 days and accumulates 3.35" (85mm) of precipitation.

How much does it rain in December?

In Copalis Crossing, in December, it is raining for 18.5 days, with typically 3.35" (85mm) of accumulated precipitation.

When it does not snow?

In Copalis Crossing, snow does not fall in April through October and December.

Does it snow in December?

In December, it doesn't snow. November is the latest month when it typically snows.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 8h and 36min of daylight.

How many hours of daylight does Copalis Crossing have in December?

In Copalis Crossing, Washington, the average day length in December is 8h and 34min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:42 am and sunset at 4:28 pm. On the last day of the month, sunrise is at 8:02 am and sunset at 4:36 pm PST.

How long on average sun shines in December?

In December, the average sunshine duration is 3.6h.

When is the lowest UV index?

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2.

How high is the UV index in December?

The average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Copalis Crossing, WA

Average temperature in December - Copalis Crossing, 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 Crossing, WA

Average pressure in December - Copalis Crossing, 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 Crossing, WA

Average wind speed in December - Copalis Crossing, 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 Crossing, WA

Average humidity in December - Copalis Crossing, 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 Crossing, WA

Average rainfall in December - Copalis Crossing, 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 Crossing, WA

Average rainfall days in December - Copalis Crossing, 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 Crossing, WA

Average snowfall in December - Copalis Crossing, 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 Crossing, WA

Average snowfall days in December - Copalis Crossing, 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 Crossing, WA

Average daylight in December / Average sunshine in December - Copalis Crossing, WA
  • Average daylight in December: 8h and 4min

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 4min

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 Crossing, WA

Average sunshine days in December - Copalis Crossing, 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 Crossing, WA

Average UV index in December - Copalis Crossing, 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 Crossing, WA

Average cloud cover in December - Copalis Crossing, 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 Crossing, WA

Average visibility in December - Copalis Crossing, 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).

Copalis Crossing, Washington, USA

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