December weather forecastNapa Junction, SD
December
Weather in December
December, the first month of the winter in Napa Junction, is also a subzero cold month, with an average temperature fluctuating between 18°F (-7.8°C) and 29.8°F (-1.2°C).Temperature
As December arrives, Napa Junction's weather displays a notable decrease in high-temperatures, falling from November's frosty 45.9°F (7.7°C) to a subzero cold 29.8°F (-1.2°C). Throughout December, Napa Junction encounters an average temperature drop to a still freezing cold 18°F (-7.8°C).Humidity
In December, the average relative humidity is 82%.Rainfall
In Napa Junction, in December, during 3.7 rainfall days, 1.18" (30mm) of precipitation is typically accumulated. In Napa Junction, during the entire year, the rain falls for 117.9 days and collects up to 21.93" (557mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. December is the month with the most snowfall. Snow falls for 8.1 days and accumulates 2.95" (75mm) of snow.Daylight
With an average of 9h and 6min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:41 am and sunset at 4:56 pm. On the last day of December, sunrise is at 8:00 am and sunset at 5:05 pm CST.
Sunshine
In December, the average sunshine in Napa Junction is 4.7h.UV index
In Napa Junction, the average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a minimal health hazard from unsafe exposure to UV radiation for average individuals.Note: In December, a regular UV index of 2 translates into these guidelines:
Prolonged exposure to sunlight rarely troubles the majority, but constant protection is vital for babies, children, and fair-skinned people. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. Take heed! Reflection from the snow can almost amplify the Sun's UV radiation by double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Napa Junction, SD
- Average high temperature in December: 29.8°F
The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is January (26.8°F).
- Average low temperature in December: 18°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (12.9°F).
Average pressure in December
Napa Junction, SD
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in December
Napa Junction, SD
- Average wind speed in December: 10.3mph
The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.9mph).
Average humidity in December
Napa Junction, SD
- Average humidity in December: 82%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is October (64%).
Average rainfall in December
Napa Junction, SD
- Average rainfall in December: 1.18"
The wettest month (with the highest rainfall) is May (3.78").
The driest month (with the least rainfall) is February (0.59").
Average rainfall days in December
Napa Junction, SD
- Average rainfall days in December: 3.7 days
The month with the highest number of rainy days is June (17.4 days).
The month with the least rainy days is February (2.3 days).
Average snowfall in December
Napa Junction, SD
- Average snowfall in December: 2.95"
The month with the highest snowfall is December (2.95").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Napa Junction, SD
- Average snowfall days in December: 8.1 days
The month with the highest number of snowfall days is January (9.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Napa Junction, SD
- Average daylight in December: 9h and 6min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in December: 4h and 42min
The month with the most sunshine is July (Average sunshine: 10h and 48min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).
Average sunshine days in December
Napa Junction, SD
- Average sunshine days in December: 21.3 days
The month with the most sunshine days is November (21.5 days).
The month with the least sunshine days is June (9.3 days).
Average UV index in December
Napa Junction, SD
- Average UV index in December: 2
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in December
Napa Junction, SD
- Average cloud cover in December: 48
The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is July (Cloud cover 25).
Average visibility in December
Napa Junction, SD
- 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).
