December weather forecast
Rainier, OR

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Weather in December

December, the first month of the winter in Rainier, is also a wintry month, with an average temperature fluctuating between 42.3°F (5.7°C) and 32.7°F (0.4°C).

Temperature

December tends to be the coldest month, with temperatures averaging a daily high of 42.3°F (5.7°C) and a low of 32.7°F (0.4°C).

Humidity

January, February, November and December, with an average relative humidity of 88%, are the most humid months.

Rainfall

In December, the rain falls for 18.5 days. Throughout December, 3.58" (91mm) of precipitation is accumulated. Throughout the year, there are 175.5 rainfall days, and 25.83" (656mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Rainier are January through March, November and December. In December, it is snowing for 0.9 days. Throughout December, 0.24" (6mm) of snow is accumulated. In Rainier, during the entire year, snow falls for 6.7 days and aggregates up to 3.54" (90mm) of snow.

Daylight

With an average of 8h and 42min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 7:34 am and sunset at 4:27 pm. On the last day of the month, sunrise is at 7:53 am and sunset at 4:36 pm PST.

Sunshine

The months with the least sunshine are January, February and December, with an average of 3.5h of sunshine.

UV index

In December, the average daily maximum UV index is 2. A UV Index value of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV rays for average individuals.
Note: A daily maximum UV index of 2 in December translates into the following instructions:
Most individuals face no major issues with lengthy exposure to the sun, but children, infants, and individuals with fair skin always require protection. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Be watchful! The reflection of snow can enhance the intensity of the Sun's UV radiation nearly double.
Updated: Aug 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What part of the year is the coldest in Rainier?

With an average high-temperature of 42.3°F (5.7°C) and an average low-temperature of 32.7°F (0.4°C), December is the coldest month.

How cold is it in December?

During December, Rainier experiences an average high-temperature of 42.3°F (5.7°C) and a low-temperature of 32.7°F (0.4°C).

What is the most humid month?

January, February, November and December, with an average relative humidity of 88%, are most humid months.

What is the average humidity in December?

The average relative humidity in December is 88%.

How much does it rain in December?

In Rainier, in December, during 18.5 rainfall days, 3.58" (91mm) of precipitation is typically accumulated.

How many days does it snow in December?

In Rainier, during December, snow falls for 0.9 days and regularly aggregates up to 0.24" (6mm) of snow.

What is the month with the shortest days?

With an average of 8h and 42min of daylight, December has the shortest days of the year in Rainier.

How many hours of daylight does Rainier have in December?

The average day length in December is 8h and 42min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:34 am and sunset at 4:27 pm. On the last day of the month, sunrise is at 7:53 am and sunset at 4:36 pm PST.

What is the month with the least sunshine?

January, February and December, with an average of 3.5h of sunshine, are months with the least sunshine.

How long on average sun shines in December?

In Rainier, Oregon, the average sunshine duration in December is 3.5h.

What is the UV index reading in December?

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 unsafe exposure to Sun's UV rays.
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
Rainier, OR

Average temperature in December - Rainier, OR
  • Average high temperature in December: 42.3°F

The warmest month (with the highest average high temperature) is August (77.9°F).
The month with the lowest average high temperature is December (42.3°F).

  • Average low temperature in December: 32.7°F

The month with the highest average low temperature is August (49.8°F).
The coldest month (with the lowest average low temperature) is December (32.7°F).

Average pressure in December
Rainier, OR

Average pressure in December - Rainier, OR
  • Average pressure in December: 30.09"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).

Average wind speed in December
Rainier, OR

Average wind speed in December - Rainier, OR
  • Average wind speed in December: 4.7mph

The windiest month (with the highest average wind speed) is January (4.8mph).
The calmest month (with the lowest average wind speed) is September (3.9mph).

Average humidity in December
Rainier, OR

Average humidity in December - Rainier, OR
  • Average humidity in December: 88%

The months with the highest relative humidity are January, February, November and December (88%).
The month with the lowest relative humidity is July (72%).

Average rainfall in December
Rainier, OR

Average rainfall in December - Rainier, OR
  • Average rainfall in December: 3.58"

The wettest month (with the highest rainfall) is January (3.9").
The driest month (with the least rainfall) is August (0.39").

Average rainfall days in December
Rainier, OR

Average rainfall days in December - Rainier, OR
  • Average rainfall days in December: 18.5 days

The month with the highest number of rainy days is March (20.3 days).
The month with the least rainy days is July (6.1 days).

Average snowfall in December
Rainier, OR

Average snowfall in December - Rainier, OR
  • Average snowfall in December: 0.24"

The month with the highest snowfall is January (1.26").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in December
Rainier, OR

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

The month with the highest number of snowfall days is February (2.2 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
Rainier, OR

Average daylight in December / Average sunshine in December - Rainier, OR
  • Average daylight in December: 8h and 4min

The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).

  • Average sunshine in December: 3h and 3min

The month with the most sunshine is August (Average sunshine: 10h and 24min).
The months with the least sunshine are January, February and December (Average sunshine: 3h and 30min).

Average sunshine days in December
Rainier, OR

Average sunshine days in December - Rainier, OR
  • Average sunshine days in December: 10.2 days

The month with the most sunshine days is July (22 days).
The month with the least sunshine days is March (8.9 days).

Average UV index in December
Rainier, OR

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

The months with the highest UV index are June and July (UV index 5).
The month with the lowest UV index is November (UV index 1).

Average cloud cover in December
Rainier, OR

Average cloud cover in December - Rainier, OR
  • Average cloud cover in December: 64

The months with the most cloud cover are February and March (Cloud cover 65).
The month with the least cloud cover is August (Cloud cover 36).

Average visibility in December
Rainier, OR

Average visibility in December - Rainier, OR
  • Average visibility in December: 4mi

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

Rainier, Oregon, USA

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