December weather forecastSpearfish, SD
December
Weather in December
December serves as the gateway to winter in Spearfish with average high temperatures hovering around a chilly 30.9°F (-0.6°C). The culmination of the year witnesses a noticeable spike in snowfall, painting the city white. Reduced daylight and the dwindling number of sunny days upholster the crisp and cold conditions. Amidst the festive spirit, the weather sets in a classic winter scene. Despite a seasonally low pressure, strong winds characterize the month, introducing a chilly spell to close the year.Temperature
Temperature readings reach their annual highs in December, averaging 30.9°F (-0.6°C) and a minimum average of 18.5°F (-7.5°C).Humidity
In December, the average relative humidity in Spearfish is 76%.Rainfall
In Spearfish, in December, during 3.5 rainfall days, 0.71" (18mm) of precipitation is typically accumulated. Throughout the year, in Spearfish, there are 99.6 rainfall days, and 15.63" (397mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, September through December. In Spearfish, in December, during 9 snowfall days, 4.09" (104mm) of snow is typically accumulated. In Spearfish, South Dakota, during the entire year, snow falls for 56.8 days and aggregates up to 36.3" (922mm) of snow.Daylight
With an average of 8h and 54min of daylight, December has the shortest days of the year in Spearfish.On the first day of the month, sunrise is at 7:12 am and sunset at 4:17 pm. On the last day of December, in Spearfish, sunrise is at 7:31 am and sunset at 4:25 pm MST.
Sunshine
In Spearfish, the average sunshine in December is 5.8h.UV index
January, February, April, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a low threat to health from unsafe exposure to UV radiation for ordinary individuals.Note: The daily high UV index of 2 during December translates into the following recommendations:
While extended sun exposure does not significantly affect most people, those with sensitive skin, children, and infants should always be protected. The solar radiation around mid-day is intense; avoid the Sun and stay safe. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly. Observe! Snow reflection can nearly intensify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Spearfish, SD
- Average high temperature in December: 30.9°F
The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is December (30.9°F).
- Average low temperature in December: 18.5°F
The month with the highest average low temperature is July (61°F).
The coldest month (with the lowest average low temperature) is February (16.2°F).
Average pressure in December
Spearfish, SD
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).
Average wind speed in December
Spearfish, SD
- Average wind speed in December: 9.9mph
The windiest month (with the highest average wind speed) is January (10.2mph).
The calmest month (with the lowest average wind speed) is August (8mph).
Average humidity in December
Spearfish, SD
- Average humidity in December: 76%
The month with the highest relative humidity is January (79%).
The month with the lowest relative humidity is August (49%).
Average rainfall in December
Spearfish, SD
- Average rainfall in December: 0.71"
The wettest month (with the highest rainfall) is May (2.32").
The driest month (with the least rainfall) is January (0.59").
Average rainfall days in December
Spearfish, SD
- Average rainfall days in December: 3.5 days
The month with the highest number of rainy days is May (15.6 days).
The month with the least rainy days is February (2.9 days).
Average snowfall in December
Spearfish, SD
- Average snowfall in December: 4.09"
The month with the highest snowfall is April (7.36").
The months with the least snowfall are June, July and August (0").
Average snowfall days in December
Spearfish, SD
- Average snowfall days in December: 9 days
The month with the highest number of snowfall days is February (11.2 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in December /
Average sunshine in December
Spearfish, SD
- Average daylight in December: 8h and 54min
The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in December: 5h and 48min
The month with the most sunshine is August (Average sunshine: 11h and 42min).
The month with the least sunshine is February (Average sunshine: 5h and 42min).
Average sunshine days in December
Spearfish, SD
- Average sunshine days in December: 19.9 days
The month with the most sunshine days is November (20.3 days).
The month with the least sunshine days is May (12.7 days).
Average UV index in December
Spearfish, SD
- Average UV index in December: 2
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, April, November and December (UV index 2).
Average cloud cover in December
Spearfish, SD
- Average cloud cover in December: 39
The month with the most cloud cover is February (Cloud cover 41).
The month with the least cloud cover is August (Cloud cover 16).
Average visibility in December
Spearfish, 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).
