December weather forecast
Wilsonville, OR

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A row of beautiful modern homes in a leafy suburb spot in Wilsonville, Oregon
A row of beautiful modern homes in a leafy suburb spot in Wilsonville, Oregon

Weather in December

In December, Wilsonville, Oregon’s weather veers towards a wintry trend. Shorter daylight hours, along with cold days and chillier nights define the climate. A significant meteorological highlight of December is the relatively high amount of rainfall, marked at 4.49" (114mm). This feature underscores how December tops the chart as the most precipitous month. With the onset of the holiday season, people take to hearty indoor activities, undercutting the wintery chill with the warmth of celebration.

Temperature

December, on average, is the coldest month, registering a high temperature of 44.2°F (6.8°C) and a low of 34.3°F (1.3°C).

Humidity

The months with the highest humidity are January, February and December, with an average relative humidity of 85%.

Rainfall

The month with the most rainfall in Wilsonville, Oregon, is December, when the rain falls for 19.4 days and typically aggregates up to 4.49" (114mm) of precipitation.

Snowfall

January through March, November and December are months with snowfall. In Wilsonville, Oregon, in December, snow falls for 0.8 days, with typically accumulated 0.47" (12mm) of snow. In Wilsonville, Oregon, during the entire year, snow falls for 6.1 days and aggregates up to 3.66" (93mm) of snow.

Daylight

December has the shortest days of the year in Wilsonville, Oregon, with an average of 8h and 48min of daylight.
On the first day of the month, sunrise is at 7:30 am and sunset at 4:29 pm. On the last day of December, in Wilsonville, Oregon, sunrise is at 7:50 am and sunset at 4:38 pm PST.

Sunshine

The average sunshine in December in Wilsonville is 4.3h.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Wilsonville. A UV Index reading of 2, and below, represents a low threat to health from exposure to the Sun's UV radiation for average individuals.
Note: The maximum daily UV index, 2 in December, converts into the following recommendations:
Extended exposure to the sun should always be avoided by children, infants, and those with sensitive skin. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun. Bear in mind! The Sun's UV radiation can nearly double in intensity due to the reflective quality of snow.
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Frequently asked questions

What is the coldest time of year in Wilsonville?

The month of December, characterized by an average high of 44.2°F (6.8°C) and a low of 34.3°F (1.3°C), is recognized as the coldest in Wilsonville, Oregon.

How cold is it in Wilsonville in December?

The average high-temperature and low-temperature in Wilsonville, Oregon, during December are 44.2°F (6.8°C) and 34.3°F (1.3°C) respectively. The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which combines relative humidity and air temperature, in August is computed to be 84.2°F (29°C).

What is the most humid month in Wilsonville?

The months with the highest humidity are January, February and December, with an average relative humidity of 85%.

What is the average humidity in December in Wilsonville?

The average relative humidity in December in Wilsonville, Oregon, is 85%.

What is the rainiest month in Wilsonville?

December is the month with the most rainfall in Wilsonville. Rain falls for 19.4 days and accumulates 4.49" (114mm) of precipitation.

How many days does it rain in December in Wilsonville?

In Wilsonville, Oregon, in December, it is raining for 19.4 days, with typically 4.49" (114mm) of accumulated precipitation.

How many days does it snow in December in Wilsonville?

In Wilsonville, Oregon, during December, snow falls for 0.8 days and regularly aggregates up to 0.47" (12mm) of snow.

What is the month with the shortest days in Wilsonville?

With an average of 8h and 48min of daylight, December has the shortest days of the year in Wilsonville.

What is the average length of the day in December in Wilsonville?

In Wilsonville, Oregon, the average day length in December is 8h and 48min.

When is the sunrise / sunset in December in Wilsonville?

In December, on the first day of the month, sunrise is at 7:30 am and sunset at 4:29 pm. On the last day of the month, in Wilsonville, Oregon, sunrise is at 7:50 am and sunset at 4:38 pm PST.

How long on average sun shines in December in Wilsonville?

In Wilsonville, Oregon, the average sunshine duration in December is 4.3h.

When is the lowest UV index in Wilsonville?

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

What is the UV index intensity in December in Wilsonville?

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 exposure to the Sun's UV radiation.
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
Wilsonville, OR

Average temperature in December - Wilsonville, OR
  • Average high temperature in December: 44.2°F

The warmest month (with the highest average high temperature) is August (81°F).
The month with the lowest average high temperature is December (44.2°F).

  • Average low temperature in December: 34.3°F

The month with the highest average low temperature is August (54°F).
The coldest month (with the lowest average low temperature) is December (34.3°F).

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Average pressure in December
Wilsonville, OR

Average pressure in December - Wilsonville, OR
  • Average pressure in December: 30.1"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).

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Average wind speed in December
Wilsonville, OR

Average wind speed in December - Wilsonville, OR
  • Average wind speed in December: 5.3mph

The windiest months (with the highest average wind speed) are January and February (5.5mph).
The calmest month (with the lowest average wind speed) is August (3.8mph).

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Average humidity in December
Wilsonville, OR

Average humidity in December - Wilsonville, OR
  • Average humidity in December: 85%

The months with the highest relative humidity are January, February and December (85%).
The month with the lowest relative humidity is August (65%).

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Average rainfall in December
Wilsonville, OR

Average rainfall in December - Wilsonville, OR
  • Average rainfall in December: 4.49"

The wettest month (with the highest rainfall) is December (4.49").
The driest months (with the least rainfall) are July and August (0.31").

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Average rainfall days in December
Wilsonville, OR

Average rainfall days in December - Wilsonville, OR
  • Average rainfall days in December: 19.4 days

The month with the highest number of rainy days is March (20.9 days).
The months with the least rainy days are July and August (4.4 days).

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Average snowfall in December
Wilsonville, OR

Average snowfall in December - Wilsonville, OR
  • Average snowfall in December: 0.47"

The month with the highest snowfall is February (1.26").
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
Wilsonville, OR

Average snowfall days in December - Wilsonville, OR
  • Average snowfall days in December: 0.8 days

The month with the highest number of snowfall days is February (2.1 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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Average daylight in December /
Average sunshine in December
Wilsonville, OR

Average daylight in December / Average sunshine in December - Wilsonville, OR
  • Average daylight in December: 8h and 5min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in December: 4h and 2min

The month with the most sunshine is August (Average sunshine: 11h and 6min).
The month with the least sunshine is February (Average sunshine: 4h and 12min).

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Average sunshine days in December
Wilsonville, OR

Average sunshine days in December - Wilsonville, OR
  • Average sunshine days in December: 10.8 days

The month with the most sunshine days is July (25 days).
The month with the least sunshine days is March (8.3 days).

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Average UV index in December
Wilsonville, OR

Average UV index in December - Wilsonville, OR
  • Average UV index in December: 2

The month with the highest UV index is July (UV index 6).
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
Wilsonville, OR

Average cloud cover in December - Wilsonville, OR
  • Average cloud cover in December: 55

The month with the most cloud cover is February (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 21).

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Average visibility in December
Wilsonville, OR

Average visibility in December - Wilsonville, OR
  • Average visibility in December: 5mi

The months with the highest visibility are July, August and September (6mi).
The months with the lowest visibility are January, February, March, April, May, June, October, November and December (5mi).

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Wilsonville, Oregon, USA

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