December weather forecast
Roche Harbor, WA

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Weather in December

December, the first month of the winter in Roche Harbor, is still a chilly month, with temperature in the range of an average low of 40.6°F (4.8°C) and an average high of 45.3°F (7.4°C).

Temperature

In Roche Harbor, the months of January, February and December are known for the lowest temperatures, reaching an average high of 45.3°F (7.4°C).

Humidity

In Roche Harbor, Washington, the average relative humidity in December is 77%.

Rainfall

In December, the rain falls for 17.6 days. Throughout December, 2.95" (75mm) of precipitation is accumulated. In Roche Harbor, during the entire year, the rain falls for 167.7 days and collects up to 23.46" (596mm) of precipitation.

Snowfall

Months with snowfall in Roche Harbor are January through March, November and December. In Roche Harbor, in December, snow falls for 1.3 days, with typically accumulated 0.31" (8mm) of snow. Throughout the year, there are 6.9 snowfall days, and 3.43" (87mm) of snow is accumulated.

Daylight

December has the shortest days of the year, with an average of 8h and 24min of daylight.
On the first day of the month, sunrise is at 7:44 am and sunset at 4:19 pm. On the last day of December, sunrise is at 8:04 am and sunset at 4:27 pm PST.

Sunshine

The month with the least sunshine is December, with an average of 4.1h of sunshine.

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 low threat to health from exposure to the Sun's UV rays for ordinary individuals.
Note: The UV index of 2 during December leads to these advisories:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Take into account! The reflection from snow can nearly double the Sun's UV radiation intensity.
Updated: Aug 23, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest month?

Roche Harbor experiences its coldest period in January, February and December, averaging a high-temperature of 45.3°F (7.4°C).

What is the usual temperature for Roche Harbor in December?

The high-temperature during December is 45.3°F (7.4°C) and the low-temperature is 40.6°F (4.8°C).

What is the average humidity in December?

The average relative humidity in December is 77%.

How many days does it rain in December?

In December, the rain falls for 17.6 days. Throughout December, 2.95" (75mm) of precipitation is accumulated.

How much does it snow in December?

In Roche Harbor, during December, snow falls for 1.3 days and regularly aggregates up to 0.31" (8mm) of snow.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 8h and 24min of daylight.

What is the average length of the day in December?

In Roche Harbor, the average day length in December is 8h and 22min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:44 am and sunset at 4:19 pm. On the last day of the month, sunrise is at 8:04 am and sunset at 4:27 pm PST.

What is the month with the least sunshine?

December has the least sunshine of the year, with an average of 4.1h of sunshine.

How long on average sun shines in December in Roche Harbor?

In Roche Harbor, the average sunshine duration in December is 4.1h.

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.

What is the UV index reading in December?

The average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a minimal hazard to health from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Roche Harbor, WA

Average temperature in December - Roche Harbor, WA
  • Average high temperature in December: 45.3°F

The warmest month (with the highest average high temperature) is July (64.9°F).
The months with the lowest average high temperature are January, February and December (45.3°F).

  • Average low temperature in December: 40.6°F

The month with the highest average low temperature is August (57.7°F).
The coldest month (with the lowest average low temperature) is February (40.5°F).

Average pressure in December
Roche Harbor, WA

Average pressure in December - Roche Harbor, WA
  • Average pressure in December: 30.06"Hg

The month with the highest atmospheric pressure is January (30.07"Hg).
The month with the lowest atmospheric pressure is March (30"Hg).

Average wind speed in December
Roche Harbor, WA

Average wind speed in December - Roche Harbor, WA
  • Average wind speed in December: 10.5mph

The windiest month (with the highest average wind speed) is November (10.7mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).

Average humidity in December
Roche Harbor, WA

Average humidity in December - Roche Harbor, WA
  • Average humidity in December: 77%

The months with the highest relative humidity are January, August and September (79%).
The month with the lowest relative humidity is April (76%).

Average rainfall in December
Roche Harbor, WA

Average rainfall in December - Roche Harbor, WA
  • Average rainfall in December: 2.95"

The wettest month (with the highest rainfall) is November (3.43").
The driest month (with the least rainfall) is July (0.43").

Average rainfall days in December
Roche Harbor, WA

Average rainfall days in December - Roche Harbor, WA
  • Average rainfall days in December: 17.6 days

The month with the highest number of rainy days is March (20.2 days).
The month with the least rainy days is August (5.3 days).

Average snowfall in December
Roche Harbor, WA

Average snowfall in December - Roche Harbor, WA
  • Average snowfall in December: 0.31"

The month with the highest snowfall is February (1.77").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in December
Roche Harbor, WA

Average snowfall days in December - Roche Harbor, WA
  • Average snowfall days in December: 1.3 days

The month with the highest number of snowfall days is February (2.7 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
Roche Harbor, WA

Average daylight in December / Average sunshine in December - Roche Harbor, WA
  • Average daylight in December: 8h and 2min

The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 24min).

  • Average sunshine in December: 4h and 1min

The month with the most sunshine is July (Average sunshine: 11h and 6min).
The month with the least sunshine is December (Average sunshine: 4h and 6min).

Average sunshine days in December
Roche Harbor, WA

Average sunshine days in December - Roche Harbor, WA
  • Average sunshine days in December: 10.6 days

The month with the most sunshine days is August (24.7 days).
The month with the least sunshine days is November (8.7 days).

Average UV index in December
Roche Harbor, WA

Average UV index in December - Roche Harbor, 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, November and December (UV index 2).

Average cloud cover in December
Roche Harbor, WA

Average cloud cover in December - Roche Harbor, WA
  • Average cloud cover in December: 56

The months with the most cloud cover are February and December (Cloud cover 56).
The months with the least cloud cover are July and August (Cloud cover 23).

Average visibility in December
Roche Harbor, WA

Average visibility in December - Roche Harbor, WA
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Roche Harbor, Washington, USA

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