December weather forecastDowners Grove, IL
December
Weather in December
December in Downers Grove is notably colder, rounding out the year with the arrival of winter. Mostly characterized by a further decline in temperature from November, this month sees a surge in snowfall to 0.75" (19mm). The daylight hours shrink significantly, resulting in noticeably shorter days and longer nights. Despite its cold disposition, December maintains decent visibility throughout, creating magical snow-covered landscapes. The higher relative humidity lends a chilly, raw feel to the air, wrapping the year in a cool winter cloak.Temperature
A shift in Downers Grove's weather is observed as November turns into December, with the average high temperature reducing from a frosty 45.7°F (7.6°C) to an icy 34.5°F (1.4°C). An average low-temperature of 25°F (-3.9°C) marks the month of December.Humidity
The average relative humidity in December is 81%.Rainfall
The month with the least rainfall is December, when the rain falls for 4.9 days and typically collects 0.63" (16mm) of precipitation.Snowfall
January through April, October through December are months with snowfall. In Downers Grove, in December, during 7.2 snowfall days, 0.75" (19mm) of snow is typically accumulated. In Downers Grove, during the entire year, snow falls for 34.9 days and aggregates up to 7.2" (183mm) of snow.Daylight
With an average of 9h and 12min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:00 am and sunset at 4:22 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 4:31 pm CST.
Sunshine
The average sunshine in December in Downers Grove is 4.1h.UV index
The average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a low threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: The average daily UV index of 2 in December transforms into the following instructions:
In contrast to children, who must always be shielded from the sun, most people can tolerate up to an hour of sun exposure without any burns. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation. Be cautious! The UV radiation from the Sun can be magnified almost twofold by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Downers Grove, IL
- Average high temperature in December: 34.5°F
The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (28.8°F).
- Average low temperature in December: 25°F
The month with the highest average low temperature is July (66.4°F).
The coldest month (with the lowest average low temperature) is January (17.1°F).
Average pressure in December
Downers Grove, IL
- Average pressure in December: 30.09"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in December
Downers Grove, IL
- Average wind speed in December: 9mph
The windiest month (with the highest average wind speed) is January (9.7mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).
Average humidity in December
Downers Grove, IL
- Average humidity in December: 81%
The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (72%).
Average rainfall in December
Downers Grove, IL
- Average rainfall in December: 0.63"
The wettest month (with the highest rainfall) is May (1.97").
The driest month (with the least rainfall) is December (0.63").
Average rainfall days in December
Downers Grove, IL
- Average rainfall days in December: 4.9 days
The month with the highest number of rainy days is May (14.9 days).
The month with the least rainy days is February (4.2 days).
Average snowfall in December
Downers Grove, IL
- Average snowfall in December: 0.75"
The month with the highest snowfall is February (2.28").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Downers Grove, IL
- Average snowfall days in December: 7.2 days
The month with the highest number of snowfall days is January (9.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Downers Grove, IL
- Average daylight in December: 9h and 12min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in December: 4h and 6min
The month with the most sunshine is August (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in December
Downers Grove, IL
- Average sunshine days in December: 20.7 days
The month with the most sunshine days is December (20.7 days).
The month with the least sunshine days is July (11.8 days).
Average UV index in December
Downers Grove, IL
- Average UV index in December: 2
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in December
Downers Grove, IL
- Average cloud cover in December: 59
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility in December
Downers Grove, 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).
