December weather forecast
Union Center, SD

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Weather in December

December, the first month of the winter in Union Center, is also an icy month, with an average temperature fluctuating between 32.2°F (0.1°C) and 18.9°F (-7.3°C).

Temperature

During the coldest month, December, temperatures average a high of 32.2°F (0.1°C) and a low of 18.9°F (-7.3°C).

Humidity

In December, the average relative humidity is 75%.

Rainfall

In Union Center, in December, during 5.8 rainfall days, 0.75" (19mm) of precipitation is typically accumulated. Throughout the year, there are 126.3 rainfall days, and 16.77" (426mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, September through December. In Union Center, during December, snow falls for 9.9 days and regularly aggregates up to 4.06" (103mm) of snow. In Union Center, during the entire year, snow falls for 62.1 days and aggregates up to 36.26" (921mm) of snow.

Daylight

With an average of 8h and 54min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:07 am and sunset at 4:12 pm. On the last day of December, sunrise is at 7:27 am and sunset at 4:20 pm MST.

Sunshine

In Union Center, the average sunshine in December is 6h.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unsafe exposure to UV radiation for ordinary individuals.
Note: The UV index of 2 during December translates into the following guidance:
Babies, children, and those with sensitive skin should always avoid extended periods in the sun. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. On your guard! Snow's reflection can almost double the intensity of the Sun's UV radiation.
Updated: Jul 21, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What month is the coldest?

In Union Center, December registers the lowest temperatures, averaging 32.2°F (0.1°C) at the peak and 18.9°F (-7.3°C) at the lowest.

How cold is December?

The high-temperature, in December, in Union Center, is 32.2°F (0.1°C), while the low-temperature averages to 18.9°F (-7.3°C). The average heat index (a.k.a. 'feels like', 'felt air temperature'), which combines relative humidity and air temperature, in August is calculated to be 82.4°F (28°C).

What is the average humidity in December?

In Union Center, South Dakota, the average relative humidity in December is 75%.

How many days does it rain in December?

In December, the rain falls for 5.8 days. Throughout December, 0.75" (19mm) of precipitation is accumulated.

How many days does it snow in December?

In December, it is snowing for 9.9 days. Throughout December, 4.06" (103mm) of snow is accumulated.

What is the month with the shortest days?

With an average of 8h and 54min of daylight, December has the shortest days of the year.

How many hours of daylight does Union Center have in December?

The average day length in December is 8h and 53min.

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:07 am and sunset at 4:12 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 4:20 pm MST.

How long on average sun shines in December?

The average sunshine duration in December is 6h.

When is the lowest UV index?

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index.

How high is the UV index in December?

In December, the average daily maximum UV index is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Union Center, SD

Average temperature in December - Union Center, SD
  • Average high temperature in December: 32.2°F

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is December (32.2°F).

  • Average low temperature in December: 18.9°F

The month with the highest average low temperature is July (62.4°F).
The coldest month (with the lowest average low temperature) is February (18°F).

Average pressure in December
Union Center, SD

Average pressure in December - Union Center, 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
Union Center, SD

Average wind speed in December - Union Center, SD
  • Average wind speed in December: 9.8mph

The windiest month (with the highest average wind speed) is October (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (8.3mph).

Average humidity in December
Union Center, SD

Average humidity in December - Union Center, SD
  • Average humidity in December: 75%

The month with the highest relative humidity is January (77%).
The months with the lowest relative humidity are August and September (49%).

Average rainfall in December
Union Center, SD

Average rainfall in December - Union Center, SD
  • Average rainfall in December: 0.75"

The wettest month (with the highest rainfall) is May (2.52").
The driest month (with the least rainfall) is January (0.59").

Average rainfall days in December
Union Center, SD

Average rainfall days in December - Union Center, SD
  • Average rainfall days in December: 5.8 days

The month with the highest number of rainy days is May (17.3 days).
The month with the least rainy days is December (5.8 days).

Average snowfall in December
Union Center, SD

Average snowfall in December - Union Center, SD
  • Average snowfall in December: 4.06"

The month with the highest snowfall is April (8.23").
The months with the least snowfall are June, July and August (0").

Average snowfall days in December
Union Center, SD

Average snowfall days in December - Union Center, SD
  • Average snowfall days in December: 9.9 days

The month with the highest number of snowfall days is February (12.8 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in December /
Average sunshine in December
Union Center, SD

Average daylight in December / Average sunshine in December - Union Center, SD
  • Average daylight in December: 8h and 5min

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: 6h and 0min

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 54min).

Average sunshine days in December
Union Center, SD

Average sunshine days in December - Union Center, SD
  • Average sunshine days in December: 17.8 days

The month with the most sunshine days is November (20 days).
The month with the least sunshine days is May (9.4 days).

Average UV index in December
Union Center, SD

Average UV index in December - Union Center, SD
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in December
Union Center, SD

Average cloud cover in December - Union Center, SD
  • Average cloud cover in December: 36

The months with the most cloud cover are February and April (Cloud cover 39).
The month with the least cloud cover is August (Cloud cover 16).

Average visibility in December
Union Center, SD

Average visibility in December - Union Center, SD
  • Average visibility in December: 6mi

The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).

Union Center, South Dakota, USA

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