December weather - Winter 2024

Weather in December
Frequently asked questions
Average temperature in December
Average pressure in December
Average wind speed in December
Average humidity in December
Average rainfall in December
Average rainfall days in December
Average snowfall in December
Average snowfall days in December
Average daylight in December
Average sunshine in December
Average sunshine days in December
Average UV index in December
Average cloud cover in December
Average visibility in December

The red tree colors of the fall along a road and amid trees in this tranquil neighborhood in Hillsboro, Oregon

Weather in December

December brings the full force of winter to Hillsboro with an average high temperature of about 43.9°F (6.6°C) and an increase in rainfall to 4.45" (113mm) on average. The dwindling daylight hours, coupled with often cloudy skies and relatively high humidity, underline the chill factor. Subtle snowfall marks the festive season, lending a white veneer to the city, though instances are sparse. Despite the cold, the festive spirit permeates the cityscape, making it an exciting period in Hillsboro. Despite grey, short days, Hillsboro sparkles with holiday lights making winter sightseeing a unique experience.

Temperature

December proves to be the coldest month in Hillsboro, Oregon, recording an average maximum temperature of 43.9°F (6.6°C) and a minimum temperature of 34°F (1.1°C).

Humidity

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

Rainfall

In Hillsboro, during December, the rain falls for 18.8 days and regularly aggregates up to 4.45" (113mm) of precipitation. Throughout the year, there are 173 rainfall days, and 29.49" (749mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through March, November and December. In Hillsboro, in December, during 0.7 snowfall days, 0.35" (9mm) of snow is typically accumulated. Throughout the year, there are 6.6 snowfall days, and 4.53" (115mm) of snow is accumulated.

Daylight

The month with the shortest days in Hillsboro, Oregon, is December, with an average of 8h and 48min of daylight.
On the first day of December in Hillsboro, sunrise is at 7:32 am and sunset at 4:30 pm. On the last day of the month, sunrise is at 7:51 am and sunset at 4:38 pm PST.

Sunshine

In Hillsboro, Oregon, the average sunshine in December is 3.9h.

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 value of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: A maximum UV index of 2 in December translates into the following recommendations:
Extended time in the sun generally does not harm most, but those with sensitive skin, infants, and children should always be protected. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. 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 month is the coldest in Hillsboro?

December proves to be the coldest month, recording an average maximum temperature of 43.9°F (6.6°C) and a minimum temperature of 34°F (1.1°C).

How cold does it get in Hillsboro in December?

December temperatures vary between a high-temperature of 43.9°F (6.6°C) and a low-temperature of 34°F (1.1°C). The average heat index (a.k.a. 'apparent temperature', 'real feel'), which represents the influence of relative humidity on air temperature, in August is calculated to be 84.2°F (29°C).

What is the most humid month in Hillsboro?

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

What is the average humidity in December in Hillsboro?

In December, the average relative humidity is 85%.

How many days does it rain in December in Hillsboro?

In Hillsboro, Oregon, in December, during 18.8 rainfall days, 4.45" (113mm) of precipitation is typically accumulated.

How much does it snow in Hillsboro in December?

In December, in Hillsboro, it is snowing for 0.7 days. Throughout December, 0.35" (9mm) of snow is accumulated.

What is the month with the shortest days in Hillsboro?

The month with the shortest days in Hillsboro is December, with an average of 8h and 48min of daylight.

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

In December, the average day length is 8h and 46min.

When is the sunrise / sunset in December in Hillsboro?

On the first day of December in Hillsboro, Oregon, sunrise is at 7:32 am and sunset at 4:30 pm. On the last day of the month, sunrise is at 7:51 am and sunset at 4:38 pm PST.

How long on average sun shines in December in Hillsboro?

In Hillsboro, the average sunshine duration in December is 3.9h.

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

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

How high is the UV index in December in Hillsboro?

The average daily maximum UV index in December in Hillsboro is 2. A UV Index value of 2, and less, symbolizes a low health threat from unprotected exposure to UV radiation.

Today

Tomorrow

Long-term

Year J F M A M J J A S O N December

Nov

December

Jan

Average high temperature

50.7°F 10.4°C

43.9°F 6.6°C

45.3°F 7.4°C

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

5.3mph 8.5km/h

5.2mph 8.4km/h

5.5mph 8.9km/h

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

Average snowfall

Average snowfall days

Average daylight

Average sunshine

Average sunshine days

10.2

10.5

10.8

Average UV index

Average cloud cover

Average visibility

Average temperature in December
Hillsboro, OR

Average high temperature in December: 43.9°F

The warmest month (with the highest average high temperature) is August (81.5°F).
The month with the lowest average high temperature is December (43.9°F).

Average low temperature in December: 34°F

The month with the highest average low temperature is August (55.4°F).
The coldest month (with the lowest average low temperature) is December (34°F).

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Average pressure in December
Hillsboro, OR

Average pressure in December: 30.1"Hg

The month with the highest atmospheric pressure is January (30.11"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).

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Average wind speed in December
Hillsboro, OR

Average wind speed in December: 4.7mph

The windiest month (with the highest average wind speed) is March (5mph).
The calmest months (with the lowest average wind speed) are June, August and September (4.3mph).

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Average humidity in December
Hillsboro, OR

Average humidity in December: 85%

The months with the highest relative humidity are January, February, November and December (85%).
The month with the lowest relative humidity is August (64%).

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Average rainfall in December
Hillsboro, OR

Average rainfall in December: 4.45"

The wettest month (with the highest rainfall) is January (4.57").
The driest month (with the least rainfall) is August (0.31").

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Average rainfall days in December
Hillsboro, OR

Average rainfall days in December: 18.8 days

The month with the highest number of rainy days is March (20.8 days).
The month with the least rainy days is August (4.4 days).

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Average snowfall in December
Hillsboro, OR

Average snowfall in December: 0.35"

The month with the highest snowfall is February (1.81").
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
Hillsboro, OR

Average snowfall days in December: 0.7 days

The month with the highest number of snowfall days is February (2.4 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
Hillsboro, 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: 3h and 5min

The month with the most sunshine is August (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 3h and 42min).

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Average sunshine days in December
Hillsboro, OR

Average sunshine days in December: 10.5 days

The month with the most sunshine days is July (24.4 days).
The month with the least sunshine days is March (8.5 days).

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Average UV index in December
Hillsboro, 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
Hillsboro, OR

Average cloud cover in December: 60

The month with the most cloud cover is February (Cloud cover 63).
The month with the least cloud cover is August (Cloud cover 25).

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Average visibility in December
Hillsboro, 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 and February (4mi).

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December weather forecast
Hillsboro, OR

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