December weather forecastProspect Heights, IL
December
Weather in December
December, the first month of the winter in Prospect Heights, is also an icy month, with an average temperature ranging between min 25°F (-3.9°C) and max 34.7°F (1.5°C).Temperature
The start of December signals a decrease in the average high-temperature, transitioning from a frosty 45.5°F (7.5°C) in November to a wintry 34.7°F (1.5°C). December brings an average low-temperature of 25°F (-3.9°C) to Prospect Heights.Humidity
In December, the average relative humidity is 80%.Rainfall
The month with the least rainfall is December, when the rain falls for 8.5 days and typically collects 1.46" (37mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. In Prospect Heights, in December, snow falls for 9.5 days, with typically accumulated 2.52" (64mm) of snow. In Prospect Heights, Illinois, during the entire year, snow falls for 43.6 days and aggregates up to 17.95" (456mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 12min of daylight.On the first day of the month, sunrise is at 7:01 am and sunset at 4:20 pm. On the last day of December, sunrise is at 7:19 am and sunset at 4:30 pm CST.
Sunshine
In Prospect Heights, the average sunshine in December is 4h.UV index
December is the month with the lowest UV index, with an average maximum UV index of 1. A UV Index of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV rays for average individuals.Note: In December, the maximum UV index of 1 transforms into these recommendations:
Most individuals face no major issues with lengthy exposure to the sun, but children, infants, and individuals with fair skin always require protection. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. 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
Prospect Heights, IL
- Average high temperature in December: 34.7°F
The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (28.2°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 (18°F).
Average pressure in December
Prospect Heights, 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
Prospect Heights, IL
- Average wind speed in December: 9.7mph
The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in December
Prospect Heights, 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
Prospect Heights, IL
- Average rainfall in December: 1.46"
The wettest month (with the highest rainfall) is May (3.9").
The driest month (with the least rainfall) is December (1.46").
Average rainfall days in December
Prospect Heights, IL
- Average rainfall days in December: 8.5 days
The month with the highest number of rainy days is May (18 days).
The month with the least rainy days is February (5.6 days).
Average snowfall in December
Prospect Heights, IL
- Average snowfall in December: 2.52"
The month with the highest snowfall is January (4.96").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Prospect Heights, IL
- Average snowfall days in December: 9.5 days
The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Prospect Heights, 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 0min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in December
Prospect Heights, IL
- Average sunshine days in December: 15.7 days
The month with the most sunshine days is November (16.3 days).
The month with the least sunshine days is June (10.7 days).
Average UV index in December
Prospect Heights, 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
Prospect Heights, 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 29).
Average visibility in December
Prospect Heights, 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).





