December weather forecastRiverdale, IL
December
Weather in December
The first month of the winter, December, is also an icy month in Riverdale, Illinois, with temperature in the range of an average low of 26.8°F (-2.9°C) and an average high of 35.8°F (2.1°C).Temperature
In December, the meteorological conditions alter, with the average high-temperature shifting from a frosty 46.8°F (8.2°C) in November to a cold 35.8°F (2.1°C). Riverdale in December observes a slight diminution in temperature from daily highs, recording a low-temperature average of 26.8°F (-2.9°C).Humidity
In December, the average relative humidity is 80%.Rainfall
February and December are months with the least rain when the rain falls for 4.2 days and typically aggregates up to 0.47" (12mm) of rain.Snowfall
Months with snowfall are January through April, October through December. In December, it is snowing for 7.5 days. Throughout December, 0.51" (13mm) of snow is accumulated. Throughout the year, there are 34.1 snowfall days, and 4.13" (105mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 12min of daylight.On the first day of December, sunrise is at 6:58 am and sunset at 4:21 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:30 pm CST.
Sunshine
In December, the average sunshine is 4h.UV index
The month with the lowest UV index is December, with an average maximum UV index of 1. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for average individuals.Note: The daily high UV index of 1 during December translates into the following recommendations:
While most people can stay under the sun for an hour without burning, children must always be guarded against sun exposure. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Heads up! The UV radiation from the Sun can almost be doubled by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Riverdale, IL
- Average high temperature in December: 35.8°F
The warmest month (with the highest average high temperature) is July (80.1°F).
The month with the lowest average high temperature is January (29.8°F).
- Average low temperature in December: 26.8°F
The month with the highest average low temperature is July (66.9°F).
The coldest month (with the lowest average low temperature) is January (19.6°F).
Average pressure in December
Riverdale, 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
Riverdale, IL
- Average wind speed in December: 10.3mph
The windiest month (with the highest average wind speed) is January (11mph).
The calmest months (with the lowest average wind speed) are July and August (6.8mph).
Average humidity in December
Riverdale, IL
- Average humidity in December: 80%
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
Riverdale, IL
- Average rainfall in December: 0.47"
The wettest months (with the highest rainfall) are May and June (1.38").
The driest months (with the least rainfall) are February and December (0.47").
Average rainfall days in December
Riverdale, IL
- Average rainfall days in December: 4.2 days
The month with the highest number of rainy days is July (14 days).
The month with the least rainy days is February (4.1 days).
Average snowfall in December
Riverdale, IL
- Average snowfall in December: 0.51"
The month with the highest snowfall is January (1.1").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Riverdale, IL
- Average snowfall days in December: 7.5 days
The month with the highest number of snowfall days is January (9.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Riverdale, IL
- Average daylight in December: 9h and 12min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in December: 4h and 0min
The month with the most sunshine is August (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in December
Riverdale, IL
- Average sunshine days in December: 19.8 days
The month with the most sunshine days is December (19.8 days).
The month with the least sunshine days is June (13.1 days).
Average UV index in December
Riverdale, IL
- Average UV index in December: 1
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in December
Riverdale, IL
- Average cloud cover in December: 59
The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in December
Riverdale, 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).
