December weather forecast and climate
Olympia, WA

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
December, the first month of the winter, in Olympia, is also a frosty month, with temperature in the range of an average low of 33.4°F (0.8°C) and an average high of 43°F (6.1°C).

Temperature

December is the coldest month, with an average high-temperature of 43°F (6.1°C) and an average low-temperature of 33.4°F (0.8°C).

Humidity

January, November and December, with an average relative humidity of 89%, are most humid months.

Rainfall

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

Snowfall

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

Daylight

With an average of 8.6h of daylight, December has the shortest days of the year.

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. A UV Index reading of 2, and below, represents a low threat to health from unsafe exposure to the UV radiation for ordinary individuals.
Note: The average daily UV index of 2 in December transform into the following instructions:
People with sensitive skin, children, and babies should always be protected from prolonged sun exposure. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.

What is the coldest month in Olympia?

December is the coldest month in Olympia, Washington, with an average high-temperature of 43°F (6.1°C) and an average low-temperature of 33.4°F (0.8°C).

What is the temperature in December in Olympia?

In December, the average high-temperature is 43°F (6.1°C), and the average low-temperature is 33.4°F (0.8°C).

What are the most humid months in Olympia?

January, November and December, with an average relative humidity of 89%, are most humid months in Olympia.

What is the average humidity in December in Olympia?

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

How much does it rain in Olympia in December?

In December, in Olympia, Washington, the rain falls for 18.8 days. Throughout December, 5.79" (147mm) of precipitation is accumulated.

What is the rainiest month in Olympia?

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

How much does it snow in Olympia in December?

In Olympia, Washington, 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?

December has the shortest days of the year in Olympia, Washington, with an average of 8.6h of daylight.

How many hours of daylight does Olympia have in December?

In Olympia, Washington, the average length of the day in December is 8.6h.

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?

In December, the average sunshine in Olympia is 3.4h.

What is the month with the lowest UV index in Olympia?

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

What is the UV index intensity in December in Olympia?

In December, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes a low health threat from unprotected exposure to the UV radiation.
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).

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

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

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).

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

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

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").

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).

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

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

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).
Months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight in December / Average sunshine in December - Olympia, WA
  • Average daylight in December: 8.6h

The month with the longest days is June (Average daylight: 15.8h).
The month with the shortest days is December (Average daylight: 8.6h).

  • Average sunshine in December: 3.4h

The month with the most sunshine is August (Average sunshine: 10.2h).
The month with the least sunshine is December (Average sunshine: 3.4h).

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).

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

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

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

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

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

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