Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
The commencement of December involves a temperature shift, with the average high-temperature dropping from a frosty 45.9°F (7.7°C) in November to a cold 35.1°F (1.7°C). Nights in December exhibit a minor reduction to an average low temperature of 26.6°F (-3°C).Humidity
In December, the average relative humidity in River Forest is 80%.Rainfall
December is the month with the least rainfall. Rain falls for 8.2 days and accumulates 1.57" (40mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In December, it is snowing for 8.3 days. Throughout December, 2.52" (64mm) of snow is accumulated. Throughout the year, there are 40.3 snowfall days, and 16.81" (427mm) of snow is accumulated.Daylight
With an average of 9h and 12min of daylight, December has the shortest days of the year.On the first day of December in River Forest, sunrise is at 7:00 am and sunset at 4:21 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 4:30 pm CST.
Sunshine
In River Forest, the average sunshine in December is 4.1h.UV index
The months with the lowest UV index are January and December, with an average maximum UV index of 1. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: The maximum daily UV index of 1 in December converts into the following recommendations:
While sun exposure does not greatly affect most, individuals with fair skin, babies, and children always need vigilant safeguarding. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Frequently asked questions
How cold is it in River Forest in December?
What is the average humidity in December in River Forest?
What is the driest month in River Forest?
How many days does it rain in December in River Forest?
How much does it snow in River Forest in December?
What is the month with the shortest days in River Forest?
How many hours of daylight does River Forest have in December?
What time are sunrise and sunset in December in River Forest?
How many hours of sunshine does River Forest have in December?
What is the month with the lowest UV index in River Forest?
How high is the UV index in December in River Forest?
Average temperature in December
River Forest, IL
- Average high temperature in December: 35.1°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (28.9°F).
- Average low temperature in December: 26.6°F
The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (19.4°F).
Average pressure in December
River Forest, 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
River Forest, IL
- Average wind speed in December: 10.4mph
The windiest month (with the highest average wind speed) is January (11.1mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).
Average humidity in December
River Forest, IL
- Average humidity in December: 80%
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is October (72%).
Average rainfall in December
River Forest, IL
- Average rainfall in December: 1.57"
The wettest month (with the highest rainfall) is May (4.49").
The driest month (with the least rainfall) is December (1.57").
Average rainfall days in December
River Forest, IL
- Average rainfall days in December: 8.2 days
The month with the highest number of rainy days is May (18.8 days).
The month with the least rainy days is February (5.1 days).
Average snowfall in December
River Forest, IL
- Average snowfall in December: 2.52"
The month with the highest snowfall is February (4.69").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
River Forest, IL
- Average snowfall days in December: 8.3 days
The month with the highest number of snowfall days is January (10.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
River Forest, IL
- Average daylight in December: 9h and 1min
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 1min
The month with the most sunshine is August (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in December
River Forest, IL
- Average sunshine days in December: 16.7 days
The month with the most sunshine days is December (16.7 days).
The month with the least sunshine days is July (9.9 days).
Average UV index in December
River Forest, IL
- Average UV index in December: 1
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
River Forest, IL
- Average cloud cover in December: 58
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in December
River Forest, 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).
River Forest, Illinois, USA
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