December weather forecastRock River, WY
December
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.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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).
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).
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).
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%).
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").
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).
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").
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).
Average daylight in December /
Average sunshine in December
Rock River, WY
- Average daylight in December: 9h and 12min
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 24min
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).
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).
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).
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).
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).
