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 arrival of December corresponds with a shift in temperature, down from a frosty 44.6°F (7°C) in November to an icy 32.9°F (0.5°C). December's average low-temperature reading settles at a subzero cold 22.8°F (-5.1°C).Humidity
The average relative humidity in December in Crystal Lake is 82%.Rainfall
November and December are months with the least rain when the rain falls for 7.9 days and typically aggregates up to 0.94" (24mm) of rain.Snowfall
Months with snowfall in Crystal Lake are January through May, October through December. In Crystal Lake, in December, snow falls for 10.9 days, with typically accumulated 1.89" (48mm) of snow. In Crystal Lake, Illinois, during the entire year, snow falls for 48.7 days and aggregates up to 11.85" (301mm) of snow.Daylight
The month with the shortest days in Crystal Lake is December, with an average of 9h and 12min of daylight.On the first day of December in Crystal Lake, sunrise is at 7:03 am and sunset at 4:22 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 4:31 pm CST.
Sunshine
In December, the average sunshine in Crystal Lake is 3.9h.UV index
The months with the lowest UV index in Crystal Lake are January and December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV radiation for the ordinary person.Note: The maximum daily UV index, 1 in December, converts into the following recommendations:
Those with sensitive skin, infants, and children require constant safeguarding from prolonged sun exposure. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage. Take warning! The intensity of the Sun's UV radiation can be nearly amplified twice due to snow reflection.
Frequently asked questions
How cold is December in Crystal Lake?
What is the average humidity in December in Crystal Lake?
What is the driest month in Crystal Lake?
How much does it rain in Crystal Lake in December?
How many days does it snow in December in Crystal Lake?
What is the month with the shortest days in Crystal Lake?
How many hours of daylight does Crystal Lake have in December?
When are sunrise and sunset in December in Crystal Lake?
How long on average sun shines in December in Crystal Lake?
What are the months with the lowest UV index in Crystal Lake?
How high is the UV index in December in Crystal Lake?
Average temperature in December
Crystal Lake, IL
- Average high temperature in December: 32.9°F
The warmest month (with the highest average high temperature) is July (79.5°F).
The month with the lowest average high temperature is January (27°F).
- Average low temperature in December: 22.8°F
The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is January (15.1°F).
Average pressure in December
Crystal Lake, 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
Crystal Lake, IL
- Average wind speed in December: 9.3mph
The windiest months (with the highest average wind speed) are January and February (9.9mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).
Average humidity in December
Crystal Lake, IL
- Average humidity in December: 82%
The months with the highest relative humidity are January and February (85%).
The months with the lowest relative humidity are April and October (76%).
Average rainfall in December
Crystal Lake, IL
- Average rainfall in December: 0.94"
The wettest month (with the highest rainfall) is June (2.8").
The driest months (with the least rainfall) are November and December (0.94").
Average rainfall days in December
Crystal Lake, IL
- Average rainfall days in December: 7.9 days
The month with the highest number of rainy days is July (18.5 days).
The month with the least rainy days is February (4.8 days).
Average snowfall in December
Crystal Lake, IL
- Average snowfall in December: 1.89"
The month with the highest snowfall is January (3.31").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Crystal Lake, IL
- Average snowfall days in December: 10.9 days
The month with the highest number of snowfall days is January (12.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Crystal Lake, 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: 3h and 5min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in December
Crystal Lake, IL
- Average sunshine days in December: 16.2 days
The month with the most sunshine days is November (17.3 days).
The month with the least sunshine days is July (10 days).
Average UV index in December
Crystal Lake, IL
- Average UV index in December: 1
The month with the highest UV index is August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Crystal Lake, IL
- Average cloud cover in December: 59
The month with the most cloud cover is January (Cloud cover 62).
The months with the least cloud cover are July and September (Cloud cover 32).
Average visibility in December
Crystal Lake, IL
- Average visibility in December: 6mi
The months with the highest visibility are March, April, May, June, July, September, October, November and December (6mi).
The months with the lowest visibility are January, February and August (5mi).
Crystal Lake, Illinois, USA
Weather forecast for your location
2. Allow the app to use your location
