December weather forecast
Trentwood, WA

Share

Weather in December

December, the first month of the winter in Trentwood, is also an icy month, with temperature in the range of an average high of 32°F (0°C) and an average low of 21.9°F (-5.6°C).

Temperature

In Trentwood, December is the coldest month, with temperatures averaging a high of 32°F (0°C) and a low of 21.9°F (-5.6°C).

Humidity

The average relative humidity in December is 88%.

Rainfall

In Trentwood, in December, it is raining for 8.9 days, with typically 2.2" (56mm) of accumulated precipitation. In Trentwood, during the entire year, the rain falls for 125.4 days and collects up to 17.28" (439mm) of precipitation.

Snowfall

January through May, September through December are months with snowfall. In Trentwood, during December, snow falls for 13.9 days and regularly aggregates up to 8.9" (226mm) of snow. In Trentwood, during the entire year, snow falls for 56.4 days and aggregates up to 37.4" (950mm) of snow.

Daylight

The month with the shortest days is December, with an average of 8h and 30min of daylight.
On the first day of the month, sunrise is at 7:17 am and sunset at 3:59 pm. On the last day of December, sunrise is at 7:37 am and sunset at 4:07 pm PST.

Sunshine

The months with the least sunshine are January and December, with an average of 3.8h of sunshine.

UV index

December is the month with the lowest UV index, with an average maximum UV index of 1. A UV Index of 2, and less, symbolizes a minimal health vulnerability from unsafe exposure to UV radiation for average individuals.
Note: In December, a regular UV index of 1 translates into these guidelines:
While most people can stay under the sun for an hour without burning, children must always be guarded against sun exposure. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Updated: Jun 29, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest month?

Trentwood's temperature records reveal December as the coldest month, marked by average highs of 32°F (0°C) and lows of 21.9°F (-5.6°C).

How cold is it in Trentwood in December?

In Trentwood, 32°F (0°C) is the average high-temperature and 21.9°F (-5.6°C) is the average low-temperature during December. The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which combines air temperature and relative humidity, in August is estimated at 82.4°F (28°C).

What is the average humidity in December?

In Trentwood, the average relative humidity in December is 88%.

How much does it rain in December?

In Trentwood, in December, during 8.9 rainfall days, 2.2" (56mm) of precipitation is typically accumulated.

How many days does it snow in December?

In Trentwood, in December, snow falls for 13.9 days, with typically accumulated 8.9" (226mm) of snow.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 8h and 30min of daylight.

What is the average length of the day in December?

In December, the average day length is 8h and 29min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:17 am and sunset at 3:59 pm. On the last day of the month, sunrise is at 7:37 am and sunset at 4:07 pm PST.

What is the month with the least sunshine in Trentwood?

The months with the least sunshine are January and December, with an average of 3.8h of sunshine.

How long on average sun shines in December?

In Trentwood, the average sunshine duration in December is 3.8h.

What is the month with the lowest UV index?

The month with the lowest UV index is December, with an average maximum UV index of 1.

What is the UV index reading in December?

In December, the average daily maximum UV index is 1. A UV Index reading of 2, and below, represents a low health threat from unprotected exposure to UV radiation.
Average high temperature
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
Trentwood, WA

Average temperature in December - Trentwood, WA
  • Average high temperature in December: 32°F

The warmest month (with the highest average high temperature) is August (83.3°F).
The month with the lowest average high temperature is December (32°F).

  • Average low temperature in December: 21.9°F

The month with the highest average low temperature is August (55.9°F).
The coldest month (with the lowest average low temperature) is December (21.9°F).

Average pressure in December
Trentwood, WA

Average pressure in December - Trentwood, WA
  • Average pressure in December: 30.17"Hg

The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).

Average wind speed in December
Trentwood, WA

Average wind speed in December - Trentwood, WA
  • Average wind speed in December: 4.7mph

The windiest month (with the highest average wind speed) is April (6.1mph).
The calmest month (with the lowest average wind speed) is December (4.7mph).

Average humidity in December
Trentwood, WA

Average humidity in December - Trentwood, WA
  • Average humidity in December: 88%

The month with the highest relative humidity is January (91%).
The month with the lowest relative humidity is August (43%).

Average rainfall in December
Trentwood, WA

Average rainfall in December - Trentwood, WA
  • Average rainfall in December: 2.2"

The wettest month (with the highest rainfall) is January (2.28").
The driest months (with the least rainfall) are July and August (0.35").

Average rainfall days in December
Trentwood, WA

Average rainfall days in December - Trentwood, WA
  • Average rainfall days in December: 8.9 days

The month with the highest number of rainy days is March (16 days).
The month with the least rainy days is July (5.1 days).

Average snowfall in December
Trentwood, WA

Average snowfall in December - Trentwood, WA
  • Average snowfall in December: 8.9"

The month with the highest snowfall is January (10.51").
The months with the least snowfall are June, July and August (0").

Average snowfall days in December
Trentwood, WA

Average snowfall days in December - Trentwood, WA
  • Average snowfall days in December: 13.9 days

The month with the highest number of snowfall days is December (13.9 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in December /
Average sunshine in December
Trentwood, WA

Average daylight in December / Average sunshine in December - Trentwood, WA
  • Average daylight in December: 8h and 3min

The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).

  • Average sunshine in December: 3h and 5min

The month with the most sunshine is August (Average sunshine: 12h and 0min).
The months with the least sunshine are January and December (Average sunshine: 3h and 48min).

Average sunshine days in December
Trentwood, WA

Average sunshine days in December - Trentwood, WA
  • Average sunshine days in December: 13.4 days

The month with the most sunshine days is July (24.3 days).
The month with the least sunshine days is March (10.3 days).

Average UV index in December
Trentwood, WA

Average UV index in December - Trentwood, WA
  • Average UV index in December: 1

The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is December (UV index 1).

Average cloud cover in December
Trentwood, WA

Average cloud cover in December - Trentwood, WA
  • Average cloud cover in December: 61

The month with the most cloud cover is January (Cloud cover 62).
The months with the least cloud cover are July and August (Cloud cover 13).

Average visibility in December
Trentwood, WA

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

The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February and December (4mi).

Trentwood, Washington, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location