December weather forecast
Olympia, WA

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The calm Capitol Lake overlooking the Washington State Capitol building in Olympia, Washington
The calm Capitol Lake overlooking the Washington State Capitol building in Olympia, Washington

Weather in December

December seals the year with Olympia fully enveloped in winter. The temperature falls further, with higher chances of snowfall as compared to the previous months. Rainfall peaks with an average of 5.79" (147mm), the maximum precipitation for the year. The short daylight hours and decreased visibility due to fog can obstruct travel plans, requiring extra preparation. Despite the cold weather and frequent showers, Olympia remains a charming sight to behold during the holiday season.

Temperature

Olympia, Washington, records the coldest temperatures in December, averaging a high of 43°F (6.1°C) and a low of 33.4°F (0.8°C).

Humidity

The months with the highest humidity are January, November and December, with an average relative humidity of 89%.

Rainfall

December is the month with the most rainfall in Olympia. Rain falls for 18.8 days and accumulates 5.79" (147mm) of precipitation.

Snowfall

January through March, November and December are months with snowfall. In Olympia, in December, during 1.4 snowfall days, 0.31" (8mm) of snow is typically accumulated. Throughout the year, there are 8.7 snowfall days, and 5.31" (135mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 8h and 36min of daylight.
On the first day of December in Olympia, sunrise is at 7:37 am and sunset at 4:24 pm. On the last day of the month, sunrise is at 7:57 am and sunset at 4:32 pm PST.

Sunshine

With an average of 3.4h of sunshine, December has the least sunshine of the year.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Olympia. A UV Index of 2, and less, symbolizes a minimal health vulnerability from unsafe exposure to UV radiation for ordinary individuals.
Note: An average UV index of 2 in December transforms into this advice:
Despite most people tolerating extended sun exposure, it is critical to always protect those with sensitive skin, infants, and children. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Pay attention! The reflection of snow can enhance the Sun's UV radiation almost double.
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Frequently asked questions

What part of the year is the coldest in Olympia?

December is the coldest month in Olympia, Washington, exhibiting average temperatures of 43°F (6.1°C) at the peak and 33.4°F (0.8°C) at the base.

How cold does it get in Olympia in December?

The high-temperature, in December, in Olympia, is 43°F (6.1°C), while the low-temperature averages to 33.4°F (0.8°C).

What is the most humid month in Olympia?

The months with the highest humidity are January, November and December, with an average relative humidity of 89%.

What is the average humidity in December in Olympia?

In Olympia, the average relative humidity in December is 89%.

What is the rainiest month in Olympia?

The month with the most rainfall in Olympia, Washington, is December, when the rain falls for 18.8 days and typically aggregates up to 5.79" (147mm) of precipitation.

How many days does it rain in December in Olympia?

In Olympia, in December, during 18.8 rainfall days, 5.79" (147mm) of precipitation is typically accumulated.

How much does it snow in Olympia in December?

In Olympia, in December, during 1.4 snowfall days, 0.31" (8mm) of snow is typically accumulated.

What is the month with the shortest days in Olympia?

The month with the shortest days is December, with an average of 8h and 36min of daylight.

How many hours of daylight does Olympia have in December?

In December, the average day length in Olympia, Washington, is 8h and 35min.

When are sunrise and sunset in December in Olympia?

On the first day of December in Olympia, Washington, sunrise is at 7:37 am and sunset at 4:24 pm. On the last day of the month, sunrise is at 7:57 am and sunset at 4:32 pm PST.

What is the month with the least sunshine in Olympia?

With an average of 3.4h of sunshine, December has the least sunshine of the year.

How long on average sun shines in December in Olympia?

The average sunshine duration in December is 3.4h.

When is the lowest UV index in Olympia?

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

How high is the UV index in December in Olympia?

The average daily maximum UV index in December in Olympia, Washington, is 2. A UV Index of 2, and less, symbolizes a minimal hazard to health from exposure to the Sun's UV radiation.
Average max. wind speed
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
Olympia, WA

Average temperature in December - Olympia, WA
  • Average high temperature in December: 43°F

The warmest month (with the highest average high temperature) is August (78.6°F).
The month with the lowest average high temperature is December (43°F).

  • Average low temperature in December: 33.4°F

The month with the highest average low temperature is August (50.5°F).
The coldest month (with the lowest average low temperature) is December (33.4°F).

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Average pressure in December
Olympia, WA

Average pressure in December - Olympia, WA
  • Average pressure in December: 30.08"Hg

The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is March (30.01"Hg).

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Average wind speed in December
Olympia, WA

Average wind speed in December - Olympia, WA
  • Average wind speed in December: 4.2mph

The windiest months (with the highest average wind speed) are March and November (4.6mph).
The calmest month (with the lowest average wind speed) is September (3.8mph).

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Average humidity in December
Olympia, WA

Average humidity in December - Olympia, WA
  • Average humidity in December: 89%

The months with the highest relative humidity are January, November and December (89%).
The month with the lowest relative humidity is July (71%).

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Average rainfall in December
Olympia, WA

Average rainfall in December - Olympia, WA
  • Average rainfall in December: 5.79"

The wettest month (with the highest rainfall) is December (5.79").
The driest month (with the least rainfall) is July (0.39").

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Average rainfall days in December
Olympia, WA

Average rainfall days in December - Olympia, WA
  • Average rainfall days in December: 18.8 days

The month with the highest number of rainy days is March (20.4 days).
The month with the least rainy days is August (5.5 days).

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Average snowfall in December
Olympia, WA

Average snowfall in December - Olympia, WA
  • Average snowfall in December: 0.31"

The month with the highest snowfall is February (2.32").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in December
Olympia, WA

Average snowfall days in December - Olympia, WA
  • Average snowfall days in December: 1.4 days

The month with the highest number of snowfall days is February (3.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight in December /
Average sunshine in December
Olympia, WA

Average daylight in December / Average sunshine in December - Olympia, 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 2min

The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is December (Average sunshine: 3h and 24min).

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Average sunshine days in December
Olympia, WA

Average sunshine days in December - Olympia, WA
  • Average sunshine days in December: 9.8 days

The month with the most sunshine days is August (22.4 days).
The month with the least sunshine days is February (8.4 days).

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Average UV index in December
Olympia, WA

Average UV index in December - Olympia, WA
  • Average UV index in December: 2

The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in December
Olympia, WA

Average cloud cover in December - Olympia, WA
  • Average cloud cover in December: 65

The months with the most cloud cover are January and December (Cloud cover 65).
The months with the least cloud cover are July and August (Cloud cover 35).

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Average visibility in December
Olympia, WA

Average visibility in December - Olympia, WA
  • Average visibility in December: 4mi

The months with the highest visibility are June, July and August (5mi).
The months with the lowest visibility are January, February, March, April, May, September, October, November and December (4mi).

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Olympia, Washington, USA

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