December weather forecast
Rock River, WY

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Weather in December

December, the first month of the winter in Rock River, is still a freezing cold month, with an average temperature fluctuating between 14.4°F (-9.8°C) and 28.2°F (-2.1°C).

Temperature

With its high average temperature of 28.2°F (-2.1°C) and a low of 14.4°F (-9.8°C), December is regarded as the coldest month.

Humidity

In December, the average relative humidity in Rock River is 74%.

Rainfall

In Rock River, in December, during 3.2 rainfall days, 0.51" (13mm) of precipitation is typically accumulated. Throughout the year, there are 101.4 rainfall days, and 14.37" (365mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Rock River are January through June, September through December. In Rock River, in December, snow falls for 8.8 days, with typically accumulated 3.46" (88mm) of snow. Throughout the year, there are 78.1 snowfall days, and 44.8" (1138mm) of snow is accumulated.

Daylight

With an average of 9h and 12min of daylight, December has the shortest days of the year in Rock River.
On the first day of December in Rock River, Wyoming, sunrise is at 7:12 am and sunset at 4:34 pm. On the last day of the month, sunrise is at 7:30 am and sunset at 4:43 pm MST.

Sunshine

The month with the least sunshine is December, with an average of 6.4h of sunshine.

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 minimal health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: An average UV index of 2 in December transforms into this advice:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days. Take heed! The reflection of snow can intensify the Sun's UV radiation nearly double.
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Frequently asked questions

What is the coldest time of year in Rock River?

Rock River's coldest month, December, registers temperatures that range from a high of 28.2°F (-2.1°C) to a low of 14.4°F (-9.8°C).

How cold is it in Rock River in December?

The high-temperature during December is 28.2°F (-2.1°C) and the low-temperature is 14.4°F (-9.8°C).

What is the average humidity in December in Rock River?

In Rock River, Wyoming, the average relative humidity in December is 74%.

How many days does it rain in December in Rock River?

In December, in Rock River, the rain falls for 3.2 days. Throughout December, 0.51" (13mm) of precipitation is accumulated.

How many days does it snow in December in Rock River?

In December, it is snowing for 8.8 days. Throughout December, 3.46" (88mm) of snow is accumulated.

What is the month with the shortest days in Rock River?

The month with the shortest days in Rock River, Wyoming, is December, with an average of 9h and 12min of daylight.

How many hours of daylight does Rock River have in December?

The average day length in December in Rock River, Wyoming, is 9h and 13min.

What time are sunrise and sunset in December in Rock River?

On the first day of December in Rock River, sunrise is at 7:12 am and sunset at 4:34 pm. On the last day of the month, sunrise is at 7:30 am and sunset at 4:43 pm MST.

What is the month with the least sunshine in Rock River?

The month with the least sunshine is December, with an average of 6.4h of sunshine.

How many hours of sunshine does Rock River have in December?

In Rock River, the average sunshine duration in December is 6.4h.

When is the lowest UV index in Rock River?

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

How high is the UV index in December in Rock River?

In December, the average daily maximum UV index in Rock River is 2. A UV Index estimate of 2, and below, represents a minimal hazard to health 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
Rock River, WY

Average temperature in December - Rock River, WY
  • Average high temperature in December: 28.2°F

The warmest month (with the highest average high temperature) is July (76.8°F).
The month with the lowest average high temperature is December (28.2°F).

  • Average low temperature in December: 14.4°F

The month with the highest average low temperature is July (54.1°F).
The coldest month (with the lowest average low temperature) is December (14.4°F).

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Average pressure in December
Rock River, WY

Average pressure in December - Rock River, WY
  • Average pressure in December: 30.15"Hg

The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

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Average wind speed in December
Rock River, WY

Average wind speed in December - Rock River, WY
  • Average wind speed in December: 14.1mph

The windiest month (with the highest average wind speed) is January (14.5mph).
The calmest month (with the lowest average wind speed) is July (9.3mph).

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Average humidity in December
Rock River, WY

Average humidity in December - Rock River, WY
  • Average humidity in December: 74%

The months with the highest relative humidity are January and February (75%).
The months with the lowest relative humidity are August and September (43%).

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Average rainfall in December
Rock River, WY

Average rainfall in December - Rock River, WY
  • Average rainfall in December: 0.51"

The wettest month (with the highest rainfall) is May (2.68").
The driest month (with the least rainfall) is January (0.35").

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Average rainfall days in December
Rock River, WY

Average rainfall days in December - Rock River, WY
  • Average rainfall days in December: 3.2 days

The months with the highest number of rainy days are May and July (15.1 days).
The months with the least rainy days are January, February and November (2.9 days).

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Average snowfall in December
Rock River, WY

Average snowfall in December - Rock River, WY
  • Average snowfall in December: 3.46"

The month with the highest snowfall is April (9.76").
The months with the least snowfall are July and August (0").

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Average snowfall days in December
Rock River, WY

Average snowfall days in December - Rock River, WY
  • Average snowfall days in December: 8.8 days

The month with the highest number of snowfall days is April (12.5 days).
The months with the least snowfall days are July and August (0 days).

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Average daylight in December /
Average sunshine in December
Rock River, WY

Average daylight in December / Average sunshine in December - Rock River, WY
  • Average daylight in December: 9h and 1min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in December: 6h and 2min

The month with the most sunshine is July (Average sunshine: 11h and 36min).
The month with the least sunshine is December (Average sunshine: 6h and 24min).

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Average sunshine days in December
Rock River, WY

Average sunshine days in December - Rock River, WY
  • Average sunshine days in December: 20.6 days

The month with the most sunshine days is January (21.4 days).
The month with the least sunshine days is May (8.9 days).

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Average UV index in December
Rock River, WY

Average UV index in December - Rock River, 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).

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Average cloud cover in December
Rock River, WY

Average cloud cover in December - Rock River, WY
  • Average cloud cover in December: 31

The month with the most cloud cover is February (Cloud cover 34).
The month with the least cloud cover is September (Cloud cover 17).

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Average visibility in December
Rock River, WY

Average visibility in December - Rock River, WY
  • 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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Rock River, Wyoming, USA

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