December weather forecastChelsea, SD

December

Weather in December

The first month of the winter, December, is also a subzero cold month in Chelsea, South Dakota, with temperature in the range of an average low of 12.7°F (-10.7°C) and an average high of 25°F (-3.9°C).

Temperature

As Chelsea transitions into December, the average high-temperature shows a marked reduction, decreasing from an icy 41.7°F (5.4°C) in November to a freezing cold 25°F (-3.9°C). Chelsea registers a consistent average low-temperature of 12.7°F (-10.7°C) during December.

Humidity

The average relative humidity in December is 85%.

Rainfall

In Chelsea, in December, it is raining for 3.1 days, with typically 0.87" (22mm) of accumulated precipitation. In Chelsea, during the entire year, the rain falls for 97.2 days and collects up to 18.35" (466mm) of precipitation.

Snowfall

Months with snowfall in Chelsea are January through May, October through December. In Chelsea, South Dakota, in December, snow falls for 11.4 days, with typically accumulated 3.43" (87mm) of snow. In Chelsea, during the entire year, snow falls for 54.8 days and aggregates up to 19.13" (486mm) of snow.

Daylight

The month with the shortest days is December, with an average of 8h and 48min of daylight.
On the first day of December, sunrise is at 7:54 am and sunset at 4:54 pm. On the last day of the month, sunrise is at 8:13 am and sunset at 5:02 pm CST.

Sunshine

In December, the average sunshine is 4.3h.

UV index

In December, the average daily maximum UV index in Chelsea is 2. A UV Index reading of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: An average maximum UV index of 2 in December leads to these recommendations:
Despite the majority tolerating prolonged sun exposure, those with sensitive skin, infants, and children demand continual protection. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. During bright days, sunglasses that offer UVA and UVB defense are recommended. Keep in mind! Snow's reflective quality can nearly double the intensity of the Sun's UV radiation.
Updated: Feb 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

An average high-temperature, in December, in Chelsea, is 25°F (-3.9°C) and the average low-temperature is 12.7°F (-10.7°C). The average heat index (a.k.a. 'apparent temperature', 'real feel'), which factors the actual air temperature with the relative humidity, in August is appraised at 86°F (30°C).

In Chelsea, the average relative humidity in December is 85%.

In December, in Chelsea, the rain falls for 3.1 days. Throughout December, 0.87" (22mm) of precipitation is accumulated.

In December, it is snowing for 11.4 days. Throughout December, 3.43" (87mm) of snow is accumulated.

With an average of 8h and 48min of daylight, December has the shortest days of the year in Chelsea.

In December, the average day length in Chelsea is 8h and 49min.

In December, on the first day of the month, sunrise is at 7:54 am and sunset at 4:54 pm. On the last day of the month, sunrise is at 8:13 am and sunset at 5:02 pm CST.

In Chelsea, the average sunshine duration in December is 4.3h.

The average daily maximum UV index in December in Chelsea, South Dakota, is 2. A UV Index reading of 2, and below, represents a low health risk from exposure to Sun's UV rays.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Chelsea, SD

  • Average high temperature in December: 25°F

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (20.7°F).

  • Average low temperature in December: 12.7°F

The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is January (6.3°F).

Average pressure in December
Chelsea, SD

  • Average pressure in December: 30.13"Hg

The month with the highest atmospheric pressure is February (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).

Average wind speed in December
Chelsea, SD

  • Average wind speed in December: 9.5mph

The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (8.3mph).

Average humidity in December
Chelsea, SD

  • Average humidity in December: 85%

The month with the highest relative humidity is January (88%).
The months with the lowest relative humidity are August and September (60%).

Average rainfall in December
Chelsea, SD

  • Average rainfall in December: 0.87"

The wettest month (with the highest rainfall) is June (3.46").
The driest month (with the least rainfall) is January (0.59").

Average rainfall days in December
Chelsea, SD

  • Average rainfall days in December: 3.1 days

The month with the highest number of rainy days is June (15 days).
The month with the least rainy days is February (2 days).

Average snowfall in December
Chelsea, SD

  • Average snowfall in December: 3.43"

The month with the highest snowfall is January (3.82").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Chelsea, SD

  • Average snowfall days in December: 11.4 days

The month with the highest number of snowfall days is January (13 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Chelsea, SD

  • Average daylight in December: 8h and 48min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in December: 4h and 18min

The month with the most sunshine is July (Average sunshine: 11h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).

Average sunshine days in December
Chelsea, SD

  • Average sunshine days in December: 18.9 days

The month with the most sunshine days is November (20.9 days).
The month with the least sunshine days is June (12.7 days).

Average UV index in December
Chelsea, 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 and November (UV index 1).

Average cloud cover in December
Chelsea, SD

  • Average cloud cover in December: 54

The month with the most cloud cover is January (Cloud cover 57).
The months with the least cloud cover are July and August (Cloud cover 23).

Average visibility in December
Chelsea, 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).