December weather forecast
Rivergrove, OR

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Weather in December

The first month of the winter, December, is also a frosty month in Rivergrove, Oregon, with an average temperature fluctuating between 44.1°F (6.7°C) and 34.5°F (1.4°C).

Temperature

The lowest temperatures are recorded in December, with averages reaching a high of 44.1°F (6.7°C) and a low of 34.5°F (1.4°C).

Humidity

January, February and December, with an average relative humidity of 84%, are the most humid months.

Rainfall

The month with the most rainfall in Rivergrove is December, when the rain falls for 18.9 days and typically aggregates up to 4.57" (116mm) of precipitation.

Snowfall

January through March, November and December are months with snowfall. In Rivergrove, in December, snow falls for 0.9 days, with typically accumulated 0.43" (11mm) of snow. Throughout the year, there are 6.5 snowfall days, and 3.94" (100mm) of snow is accumulated.

Daylight

With an average of 8h and 48min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:31 am and sunset at 4:29 pm. On the last day of December, sunrise is at 7:50 am and sunset at 4:38 pm PST.

Sunshine

The average sunshine in December is 4.2h.

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 unprotected exposure to Sun's UV rays for the average person.
Note: A maximum high UV index of 2 in December translates into the following recommendations:
Though extended exposure to the sun typically does not concern most people, it is crucial to always shield children, infants, and those with sensitive skin. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Take into account! The reflection from snow can nearly double the Sun's UV radiation intensity.
Updated: Aug 22, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What part of the year is the coldest?

Rivergrove notes the coldest temperatures in December, with a average high of 44.1°F (6.7°C) and a low of 34.5°F (1.4°C).

How cold does it get in December?

In Rivergrove, 44.1°F (6.7°C) is the average high-temperature and 34.5°F (1.4°C) is the average low-temperature during December. In August, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which calculates the temperature value influenced by the moisture in the air, is evaluated at 84.2°F (29°C).

What is the most humid month in Rivergrove?

The months with the highest humidity in Rivergrove are January, February and December, with an average relative humidity of 84%.

What is the average humidity in December in Rivergrove?

In December, the average relative humidity is 84%.

What is the wettest month?

December is the month with the most rainfall in Rivergrove. Rain falls for 18.9 days and accumulates 4.57" (116mm) of precipitation.

How much does it rain in December?

In Rivergrove, in December, it is raining for 18.9 days, with typically 4.57" (116mm) of accumulated precipitation.

How much does it snow in December?

In Rivergrove, in December, during 0.9 snowfall days, 0.43" (11mm) of snow is typically accumulated.

What is the month with the shortest days?

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

What is the average length of the day in December?

The average day length in December is 8h and 47min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:31 am and sunset at 4:29 pm. On the last day of the month, sunrise is at 7:50 am and sunset at 4:38 pm PST.

How long on average sun shines in December?

In December, the average sunshine duration is 4.2h.

What is the month with 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 intensity in December?

The average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a low health threat 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
Rivergrove, OR

Average temperature in December - Rivergrove, OR
  • Average high temperature in December: 44.1°F

The warmest month (with the highest average high temperature) is August (82°F).
The month with the lowest average high temperature is December (44.1°F).

  • Average low temperature in December: 34.5°F

The month with the highest average low temperature is August (55°F).
The coldest month (with the lowest average low temperature) is December (34.5°F).

Average pressure in December
Rivergrove, OR

Average pressure in December - Rivergrove, 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).

Average wind speed in December
Rivergrove, OR

Average wind speed in December - Rivergrove, OR
  • Average wind speed in December: 5.2mph

The windiest month (with the highest average wind speed) is January (5.5mph).
The calmest month (with the lowest average wind speed) is August (3.9mph).

Average humidity in December
Rivergrove, OR

Average humidity in December - Rivergrove, OR
  • Average humidity in December: 84%

The months with the highest relative humidity are January, February and December (84%).
The month with the lowest relative humidity is August (63%).

Average rainfall in December
Rivergrove, OR

Average rainfall in December - Rivergrove, OR
  • Average rainfall in December: 4.57"

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

Average rainfall days in December
Rivergrove, OR

Average rainfall days in December - Rivergrove, OR
  • Average rainfall days in December: 18.9 days

The month with the highest number of rainy days is March (19.8 days).
The month with the least rainy days is August (4.8 days).

Average snowfall in December
Rivergrove, OR

Average snowfall in December - Rivergrove, OR
  • Average snowfall in December: 0.43"

The month with the highest snowfall is February (1.57").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in December
Rivergrove, OR

Average snowfall days in December - Rivergrove, OR
  • Average snowfall days in December: 0.9 days

The month with the highest number of snowfall days is February (2.3 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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

Average daylight in December / Average sunshine in December - Rivergrove, 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 1min

The month with the most sunshine is August (Average sunshine: 11h and 0min).
The month with the least sunshine is February (Average sunshine: 4h and 6min).

Average sunshine days in December
Rivergrove, OR

Average sunshine days in December - Rivergrove, OR
  • Average sunshine days in December: 10.4 days

The month with the most sunshine days is July (25 days).
The month with the least sunshine days is February (8.6 days).

Average UV index in December
Rivergrove, OR

Average UV index in December - Rivergrove, 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).

Average cloud cover in December
Rivergrove, OR

Average cloud cover in December - Rivergrove, OR
  • Average cloud cover in December: 56

The month with the most cloud cover is February (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 22).

Average visibility in December
Rivergrove, OR

Average visibility in December - Rivergrove, 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).

Rivergrove, Oregon, USA

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