December weather forecastJefferson, SD
December
Weather in December
The first month of the winter, December, is also a subzero cold month in Jefferson, South Dakota, with an average temperature varying between 30.7°F (-0.7°C) and 18.7°F (-7.4°C).Temperature
Jefferson sees a considerable decrease in average high-temperatures during December, falling from a frosty 45.9°F (7.7°C) in November to a subzero cold 30.7°F (-0.7°C). Jefferson observes an average nighttime low-temperature of 18.7°F (-7.4°C) during the month of December.Humidity
The average relative humidity in December is 81%.Rainfall
In Jefferson, during December, the rain falls for 4.1 days and regularly aggregates up to 1.22" (31mm) of precipitation. In Jefferson, during the entire year, the rain falls for 122 days and collects up to 21.61" (549mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In Jefferson, South Dakota, in December, snow falls for 8.4 days, with typically accumulated 2.56" (65mm) of snow. Throughout the year, there are 38 snowfall days, and 13.23" (336mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 6min of daylight.On the first day of December, sunrise is at 7:37 am and sunset at 4:53 pm. On the last day of the month, sunrise is at 7:56 am and sunset at 5:03 pm CST.
Sunshine
The average sunshine in December is 4.8h.UV index
The average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV radiation for average individuals.Note: The UV index of 2 in December translates into these instructions:
Children, infants, and individuals with sensitive skin should be constantly protected from extended sun exposure. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation. Be careful! The Sun's UV radiation can nearly be doubled by the reflective quality of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Jefferson, SD
- Average high temperature in December: 30.7°F
The warmest month (with the highest average high temperature) is July (84°F).
The month with the lowest average high temperature is January (27°F).
- Average low temperature in December: 18.7°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 (13.1°F).
Average pressure in December
Jefferson, 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 (29.86"Hg).
Average wind speed in December
Jefferson, SD
- Average wind speed in December: 10.2mph
The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.6mph).
Average humidity in December
Jefferson, SD
- Average humidity in December: 81%
The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (65%).
Average rainfall in December
Jefferson, SD
- Average rainfall in December: 1.22"
The wettest months (with the highest rainfall) are May and June (3.03").
The driest month (with the least rainfall) is February (0.67").
Average rainfall days in December
Jefferson, SD
- Average rainfall days in December: 4.1 days
The month with the highest number of rainy days is June (17.8 days).
The month with the least rainy days is February (3.3 days).
Average snowfall in December
Jefferson, SD
- Average snowfall in December: 2.56"
The month with the highest snowfall is January (2.95").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Jefferson, SD
- Average snowfall days in December: 8.4 days
The month with the highest number of snowfall days is January (9.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Jefferson, 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 48min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).
Average sunshine days in December
Jefferson, SD
- Average sunshine days in December: 20.1 days
The month with the most sunshine days is November (20.9 days).
The month with the least sunshine days is June (9.7 days).
Average UV index in December
Jefferson, SD
- Average UV index in December: 2
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in December
Jefferson, 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 26).
Average visibility in December
Jefferson, 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).
