December weather forecast
Newcastle, WY

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Weather in December

The year rounds off with December reintroducing the winter chill heavy enough to paint windows with frosty designs in Newcastle. Despite the cold, the city maintains a festive spirit, preparing to bid farewell to the year. Snowfall peaks in December, providing 3.98" (101mm) of fresh snow perfect for winter sports and snowmen. The snow-tipped pine trees, twining with the brightly lit houses, create a cosy atmosphere throughout the city. As daylight shrinks to its shortest duration, electric lights glow warmer in the cosy indoor spaces of Newcastle.

Temperature

Newcastle experiences its lowest average temperatures in December, reaching a peak of 26.2°F (-3.2°C) and a minimum of 11.7°F (-11.3°C).

Humidity

The average relative humidity in December is 81%.

Rainfall

The month with the least rainfall is December, when the rain falls for 4.3 days and typically collects 0.67" (17mm) of precipitation.

Snowfall

January through June, September through December are months with snowfall. In Newcastle, Wyoming, in December, snow falls for 11.7 days, with typically accumulated 3.98" (101mm) of snow. Throughout the year, there are 80.3 snowfall days, and 41.38" (1051mm) of snow is accumulated.

Daylight

With an average of 9h and 0min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:11 am and sunset at 4:20 pm. On the last day of December, in Newcastle, sunrise is at 7:30 am and sunset at 4:29 pm MST.

Sunshine

In December, the average sunshine is 5.8h.

UV index

January through April, October through December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: In December, the maximum UV index of 2 suggests this advice:
While most individuals can withstand prolonged sun exposure, it is imperative that babies, children, and those with sensitive skin always be shielded. The Sun's radiation is especially intense around midday; try to stay in shade during this period. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Observe! Snow reflection can nearly intensify the Sun's UV radiation twofold.
Updated: Aug 29, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What month is the coldest?

December is the coldest month of the year, registering average temperatures as high as 26.2°F (-3.2°C) and as low as 11.7°F (-11.3°C).

How cold is it in Newcastle in December?

The high-temperature, in December, in Newcastle, is 26.2°F (-3.2°C), while the low-temperature averages to 11.7°F (-11.3°C).

What is the average humidity in December?

In December, the average relative humidity is 81%.

What is the driest month?

The month with the least rainfall is December, when the rain falls for 4.3 days and typically collects 0.67" (17mm) of precipitation.

How many days does it rain in December?

In Newcastle, in December, during 4.3 rainfall days, 0.67" (17mm) of precipitation is typically accumulated.

How much does it snow in December?

In Newcastle, Wyoming, in December, during 11.7 snowfall days, 3.98" (101mm) of snow is typically accumulated.

What is the month with the shortest days in Newcastle?

December has the shortest days of the year, with an average of 9h and 0min of daylight.

How many hours of daylight does Newcastle have in December?

In Newcastle, the average day length in December is 8h and 58min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:11 am and sunset at 4:20 pm. On the last day of the month, sunrise is at 7:30 am and sunset at 4:29 pm MST.

How many hours of sunshine does Newcastle have in December?

In December, the average sunshine duration is 5.8h.

When is the lowest UV index?

The months with the lowest UV index are January through April, October through December, with an average maximum UV index of 2.

What is the UV index reading in December in Newcastle?

The average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a minimal hazard to health from exposure to Sun's UV rays.
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
Newcastle, WY

Average temperature in December - Newcastle, WY
  • Average high temperature in December: 26.2°F

The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is December (26.2°F).

  • Average low temperature in December: 11.7°F

The month with the highest average low temperature is July (57.7°F).
The coldest month (with the lowest average low temperature) is February (10.8°F).

Average pressure in December
Newcastle, WY

Average pressure in December - Newcastle, WY
  • Average pressure in December: 30.13"Hg

The months with the highest atmospheric pressure are January and December (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).

Average wind speed in December
Newcastle, WY

Average wind speed in December - Newcastle, WY
  • Average wind speed in December: 8.3mph

The windiest month (with the highest average wind speed) is April (10.3mph).
The calmest month (with the lowest average wind speed) is August (7.8mph).

Average humidity in December
Newcastle, WY

Average humidity in December - Newcastle, WY
  • Average humidity in December: 81%

The month with the highest relative humidity is February (84%).
The month with the lowest relative humidity is August (53%).

Average rainfall in December
Newcastle, WY

Average rainfall in December - Newcastle, WY
  • Average rainfall in December: 0.67"

The wettest months (with the highest rainfall) are June and July (2.68").
The driest month (with the least rainfall) is December (0.67").

Average rainfall days in December
Newcastle, WY

Average rainfall days in December - Newcastle, WY
  • Average rainfall days in December: 4.3 days

The month with the highest number of rainy days is June (17.9 days).
The month with the least rainy days is February (3.7 days).

Average snowfall in December
Newcastle, WY

Average snowfall in December - Newcastle, WY
  • Average snowfall in December: 3.98"

The month with the highest snowfall is April (8.82").
The months with the least snowfall are July and August (0").

Average snowfall days in December
Newcastle, WY

Average snowfall days in December - Newcastle, WY
  • Average snowfall days in December: 11.7 days

The month with the highest number of snowfall days is January (12.8 days).
The months with the least snowfall days are July and August (0 days).

Average daylight in December /
Average sunshine in December
Newcastle, WY

Average daylight in December / Average sunshine in December - Newcastle, WY
  • Average daylight in December: 9h and 0min

The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).

  • Average sunshine in December: 5h and 5min

The month with the most sunshine is August (Average sunshine: 11h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 36min).

Average sunshine days in December
Newcastle, WY

Average sunshine days in December - Newcastle, WY
  • Average sunshine days in December: 17.9 days

The month with the most sunshine days is November (18.7 days).
The month with the least sunshine days is June (9.7 days).

Average UV index in December
Newcastle, WY

Average UV index in December - Newcastle, WY
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).

Average cloud cover in December
Newcastle, WY

Average cloud cover in December - Newcastle, WY
  • Average cloud cover in December: 40

The month with the most cloud cover is February (Cloud cover 43).
The month with the least cloud cover is August (Cloud cover 17).

Average visibility in December
Newcastle, WY

Average visibility in December - Newcastle, WY
  • Average visibility in December: 5mi

The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February and December (5mi).

Newcastle, Wyoming, USA

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