December weather forecastSwansea, IL
December
Weather in December
The first month of the winter, December, is also an icy month in Swansea, Illinois, with temperature in the range of an average low of 30.6°F (-0.8°C) and an average high of 42.6°F (5.9°C).Temperature
A shift in the average high-temperature occurs in December, reducing from a cool 53.4°F (11.9°C) in November to a wintry 42.6°F (5.9°C). Swansea cools down to an average low-temperature of 30.6°F (-0.8°C) throughout the month of December.Humidity
The average relative humidity in December is 76%.Rainfall
In December, the rain falls for 8.4 days. Throughout December, 2.28" (58mm) of precipitation is accumulated. Throughout the year, there are 147.1 rainfall days, and 35.43" (900mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through March, November and December. In Swansea, during December, snow falls for 4 days and regularly aggregates up to 2.01" (51mm) of snow. Throughout the year, there are 21.1 snowfall days, and 8.11" (206mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 30min of daylight.On the first day of the month, sunrise is at 6:59 am and sunset at 4:39 pm. On the last day of December, sunrise is at 7:17 am and sunset at 4:49 pm CST.
Sunshine
In December, the average sunshine is 4.7h.UV index
January, February and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: A daily high UV index of 2 in December leads to these guidelines:
Children, infants, and individuals with sensitive skin should be constantly protected from extended sun exposure. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance. Warning! The reflection from snow can nearly magnify 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
Swansea, IL
- Average high temperature in December: 42.6°F
The warmest month (with the highest average high temperature) is July (85.8°F).
The month with the lowest average high temperature is January (37.8°F).
- Average low temperature in December: 30.6°F
The month with the highest average low temperature is July (68.4°F).
The coldest month (with the lowest average low temperature) is January (24.8°F).
Average pressure in December
Swansea, IL
- 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 (29.92"Hg).
Average wind speed in December
Swansea, IL
- Average wind speed in December: 8.7mph
The windiest month (with the highest average wind speed) is January (9.4mph).
The calmest month (with the lowest average wind speed) is July (5.6mph).
Average humidity in December
Swansea, IL
- Average humidity in December: 76%
The months with the highest relative humidity are May and July (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Swansea, IL
- Average rainfall in December: 2.28"
The wettest month (with the highest rainfall) is May (4.37").
The driest month (with the least rainfall) is February (1.93").
Average rainfall days in December
Swansea, IL
- Average rainfall days in December: 8.4 days
The month with the highest number of rainy days is May (16.4 days).
The month with the least rainy days is January (6.8 days).
Average snowfall in December
Swansea, IL
- Average snowfall in December: 2.01"
The month with the highest snowfall is January (2.4").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in December
Swansea, IL
- Average snowfall days in December: 4 days
The month with the highest number of snowfall days is January (7.3 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in December /
Average sunshine in December
Swansea, IL
- Average daylight in December: 9h and 30min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in December: 4h and 42min
The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).
Average sunshine days in December
Swansea, IL
- Average sunshine days in December: 18.2 days
The month with the most sunshine days is October (18.3 days).
The month with the least sunshine days is May (12.3 days).
Average UV index in December
Swansea, IL
- Average UV index in December: 2
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).
Average cloud cover in December
Swansea, IL
- Average cloud cover in December: 50
The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is June (Cloud cover 29).
Average visibility in December
Swansea, IL
- 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).
