December weather forecastSun Valley, ID
December
Weather in December
Rounding off the year, December sees Sun Valley fully enveloped in winter. Compared to November's transitional weather, December establishes a cold climate with highs limited to 25°F (-3.9°C) and lows dipping to 8.6°F (-13°C). A further increase in snowfall, reaching 12.05" (306mm), adorns the city in a snow blanket enhancing the year-end festivities. Limited daylight hours not only contribute to the wintry atmosphere but also induce a coziness matching the holiday season. Thus, Sun Valley's December weather thrives in its winter appeal, making it a great visit for lovers of cold and snow.Temperature
The coldest month is December, with an average high-temperature of 25°F (-3.9°C) and an average low-temperature of 8.6°F (-13°C).Humidity
In December, the average relative humidity in Sun Valley is 84%.Rainfall
In Sun Valley, Idaho, during December, the rain falls for 7 days and regularly aggregates up to 1.65" (42mm) of precipitation. In Sun Valley, Idaho, during the entire year, the rain falls for 107.7 days and collects up to 15.63" (397mm) of precipitation.Snowfall
Months with snowfall in Sun Valley are January through June, September through December. In Sun Valley, in December, snow falls for 14 days, with typically accumulated 12.05" (306mm) of snow. Throughout the year, in Sun Valley, there are 88.2 snowfall days, and 69.45" (1764mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 0min of daylight.On the first day of December in Sun Valley, sunrise is at 7:51 am and sunset at 5:01 pm. On the last day of the month, sunrise is at 8:10 am and sunset at 5:10 pm MST.
Sunshine
The average sunshine in December in Sun Valley, Idaho, is 5.8h.UV index
In December, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV rays for the ordinary person.Note: A typical high UV index of 2 in December suggests the following recommendations:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. The Sun's radiation is especially intense around midday; try to stay in shade during this period. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage. Alert! The snow's reflection can amplify the UV radiation of the Sun nearly twice.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Sun Valley, ID
- Average high temperature in December: 25°F
The warmest month (with the highest average high temperature) is July (74.1°F).
The month with the lowest average high temperature is December (25°F).
- Average low temperature in December: 8.6°F
The months with the highest average low temperature are July and August (50.5°F).
The coldest month (with the lowest average low temperature) is January (8.4°F).
Average pressure in December
Sun Valley, ID
- Average pressure in December: 30.24"Hg
The month with the highest atmospheric pressure is January (30.27"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in December
Sun Valley, ID
- Average wind speed in December: 4.7mph
The windiest month (with the highest average wind speed) is July (6.3mph).
The calmest month (with the lowest average wind speed) is January (4.5mph).
Average humidity in December
Sun Valley, ID
- Average humidity in December: 84%
The month with the highest relative humidity is February (87%).
The month with the lowest relative humidity is August (37%).
Average rainfall in December
Sun Valley, ID
- Average rainfall in December: 1.65"
The wettest month (with the highest rainfall) is March (2.01").
The driest month (with the least rainfall) is July (0.43").
Average rainfall days in December
Sun Valley, ID
- Average rainfall days in December: 7 days
The month with the highest number of rainy days is May (14.8 days).
The month with the least rainy days is July (5.9 days).
Average snowfall in December
Sun Valley, ID
- Average snowfall in December: 12.05"
The month with the highest snowfall is February (15").
The months with the least snowfall are July and August (0").
Average snowfall days in December
Sun Valley, ID
- Average snowfall days in December: 14 days
The month with the highest number of snowfall days is March (16 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in December /
Average sunshine in December
Sun Valley, ID
- 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 48min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 5h and 42min).
Average sunshine days in December
Sun Valley, ID
- Average sunshine days in December: 15.8 days
The month with the most sunshine days is July (20.8 days).
The month with the least sunshine days is April (11.1 days).
Average UV index in December
Sun Valley, ID
- Average UV index in December: 2
The months with the highest UV index are June and July (UV index 5).
The month with the lowest UV index is February (UV index 1).
Average cloud cover in December
Sun Valley, ID
- Average cloud cover in December: 40
The month with the most cloud cover is February (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 10).
Average visibility in December
Sun Valley, ID
- Average visibility in December: 4mi
The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February and December (4mi).
