December weather forecast
Richland, WA

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Weather in December

December in Richland signifies the full swing of winter. Temperatures drop significantly, making the city truly experience cold winter weather. The increased rainfall, measuring up to 0.94" (24mm), and the reemerging snowfall add to the white wintry view. The skies take a grey turn with high cloud cover and extended twilight periods. The year signs off with a hint of festive cheer battling the characteristic December chill.

Temperature

December, recording an average high temperature of 38.1°F (3.4°C) and a low temperature of 27.5°F (-2.5°C), is Richland's coldest month.

Humidity

In December, the average relative humidity in Richland is 78%.

Rainfall

The month with the most rainfall is December, when the rain falls for 10.3 days and typically aggregates up to 0.94" (24mm) of precipitation.

Snowfall

Months with snowfall are January through March, November and December. In Richland, in December, snow falls for 3.3 days, with typically accumulated 1.5" (38mm) of snow. Throughout the year, there are 10.4 snowfall days, and 5.35" (136mm) of snow is accumulated.

Daylight

December has the shortest days of the year, with an average of 8h and 42min of daylight.
On the first day of December in Richland, sunrise is at 7:20 am and sunset at 4:12 pm. On the last day of the month, sunrise is at 7:40 am and sunset at 4:20 pm PST.

Sunshine

In December, the average sunshine is 5.6h.

UV index

The months with the lowest UV index in Richland, Washington, are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: A maximum high daily UV index of 2 during December translates into the following directions:
While sun exposure does not greatly affect most, individuals with fair skin, babies, and children always need vigilant safeguarding. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays. Be advised! The UV radiation from the Sun can be almost doubled due to the reflective properties of snow.
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Frequently asked questions

What month is the coldest in Richland?

December, with an average high of 38.1°F (3.4°C) and a low of 27.5°F (-2.5°C), signifies the coldest month of the year in Richland, Washington.

How cold is December in Richland?

The average high-temperature, in December, in Richland, is 38.1°F (3.4°C), while the average low-temperature is 27.5°F (-2.5°C).

What is the average humidity in December in Richland?

The average relative humidity in December in Richland, Washington, is 78%.

What is the rainiest month in Richland?

December is the month with the most rainfall in Richland. Rain falls for 10.3 days and accumulates 0.94" (24mm) of precipitation.

How many days does it rain in December in Richland?

In December, the rain falls for 10.3 days. Throughout December, 0.94" (24mm) of precipitation is accumulated.

How many days does it snow in December in Richland?

In Richland, during December, snow falls for 3.3 days and regularly aggregates up to 1.5" (38mm) of snow.

What is the month with the shortest days in Richland?

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

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

The average day length in December is 8h and 41min.

When are sunrise and sunset in December in Richland?

On the first day of December in Richland, Washington, sunrise is at 7:20 am and sunset at 4:12 pm. On the last day of the month, sunrise is at 7:40 am and sunset at 4:20 pm PST.

How long on average sun shines in December in Richland?

The average sunshine duration in December in Richland, Washington, is 5.6h.

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

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

How high is the UV index in December in Richland?

In Richland, Washington, the average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to 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
Richland, WA

Average temperature in December - Richland, WA
  • Average high temperature in December: 38.1°F

The warmest month (with the highest average high temperature) is July (90.1°F).
The month with the lowest average high temperature is December (38.1°F).

  • Average low temperature in December: 27.5°F

The month with the highest average low temperature is August (64.2°F).
The coldest month (with the lowest average low temperature) is December (27.5°F).

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Average pressure in December
Richland, WA

Average pressure in December - Richland, WA
  • Average pressure in December: 30.16"Hg

The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).

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Average wind speed in December
Richland, WA

Average wind speed in December - Richland, WA
  • Average wind speed in December: 5.6mph

The windiest month (with the highest average wind speed) is April (8.3mph).
The calmest month (with the lowest average wind speed) is December (5.6mph).

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Average humidity in December
Richland, WA

Average humidity in December - Richland, WA
  • Average humidity in December: 78%

The month with the highest relative humidity is January (81%).
The month with the lowest relative humidity is July (35%).

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Average rainfall in December
Richland, WA

Average rainfall in December - Richland, WA
  • Average rainfall in December: 0.94"

The wettest month (with the highest rainfall) is December (0.94").
The driest months (with the least rainfall) are July and September (0.2").

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Average rainfall days in December
Richland, WA

Average rainfall days in December - Richland, WA
  • Average rainfall days in December: 10.3 days

The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is July (3.5 days).

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Average snowfall in December
Richland, WA

Average snowfall in December - Richland, WA
  • Average snowfall in December: 1.5"

The month with the highest snowfall is February (2.2").
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
Richland, WA

Average snowfall days in December - Richland, WA
  • Average snowfall days in December: 3.3 days

The month with the highest number of snowfall days is December (3.3 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
Richland, WA

Average daylight in December / Average sunshine in December - Richland, WA
  • 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: 5h and 4min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 5h and 24min).

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Average sunshine days in December
Richland, WA

Average sunshine days in December - Richland, WA
  • Average sunshine days in December: 16.6 days

The month with the most sunshine days is July (25.7 days).
The months with the least sunshine days are February and March (15.3 days).

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Average UV index in December
Richland, WA

Average UV index in December - Richland, WA
  • Average UV index in December: 2

The month with the highest UV index is July (UV index 7).
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
Richland, WA

Average cloud cover in December - Richland, WA
  • Average cloud cover in December: 42

The month with the most cloud cover is January (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 9).

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Average visibility in December
Richland, WA

Average visibility in December - Richland, WA
  • Average visibility in December: 6mi

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

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Richland, Washington, USA

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