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
Crystal Lake's transition into December is marked by a clear temperature shift, receding from an icy 42.6°F (5.9°C) in November to a subzero cold 27.7°F (-2.4°C). Crystal Lake's nights in December cool down to an average low-temperature of 17.4°F (-8.1°C).Humidity
The average relative humidity in December is 86%.Rainfall
In December, the rain falls for 5.7 days. Throughout December, 1.26" (32mm) of precipitation is accumulated. In Crystal Lake, during the entire year, the rain falls for 136.2 days and collects up to 25.39" (645mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In Crystal Lake, during December, snow falls for 12 days and regularly aggregates up to 3.35" (85mm) of snow. Throughout the year, in Crystal Lake, there are 55.1 snowfall days, and 22.05" (560mm) of snow is accumulated.Daylight
With an average of 9h and 0min of daylight, December has the shortest days of the year in Crystal Lake.On the first day of the month, sunrise is at 7:28 am and sunset at 4:40 pm. On the last day of December, sunrise is at 7:47 am and sunset at 4:49 pm CST.
Sunshine
The average sunshine in December is 4h.UV index
The months with the lowest UV index are January and December, with an average maximum UV index of 1. A UV Index of 2, and less, symbolizes a minimal health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: In December, a regular UV index of 1 translates into these guidelines:
Babies, children, and those with sensitive skin should always avoid extended periods in the sun. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Note this! The Sun's UV radiation can nearly be doubled by the reflection off snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in December?
What is the average humidity in December?
How much does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Crystal Lake have in December?
When are sunrise and sunset in December?
How many hours of sunshine does Crystal Lake have in December?
What is the month with the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Crystal Lake, IA
- Average high temperature in December: 27.7°F
The warmest month (with the highest average high temperature) is July (79.3°F).
The month with the lowest average high temperature is January (22.1°F).
- Average low temperature in December: 17.4°F
The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (9.9°F).
Average pressure in December
Crystal Lake, IA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in December
Crystal Lake, IA
- Average wind speed in December: 10.2mph
The windiest month (with the highest average wind speed) is April (10.9mph).
The calmest month (with the lowest average wind speed) is July (7.4mph).
Average humidity in December
Crystal Lake, IA
- Average humidity in December: 86%
The month with the highest relative humidity is January (89%).
The month with the lowest relative humidity is October (70%).
Average rainfall in December
Crystal Lake, IA
- Average rainfall in December: 1.26"
The wettest month (with the highest rainfall) is June (4.21").
The driest month (with the least rainfall) is January (0.98").
Average rainfall days in December
Crystal Lake, IA
- Average rainfall days in December: 5.7 days
The month with the highest number of rainy days is June (18.8 days).
The month with the least rainy days is February (3 days).
Average snowfall in December
Crystal Lake, IA
- Average snowfall in December: 3.35"
The month with the highest snowfall is February (5.79").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Crystal Lake, IA
- Average snowfall days in December: 12 days
The month with the highest number of snowfall days is January (13.3 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, IA
- Average daylight in December: 9h and 0min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in December: 4h and 0min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in December
Crystal Lake, IA
- Average sunshine days in December: 15.6 days
The months with the most sunshine days are October and November (17.4 days).
The month with the least sunshine days is June (9.2 days).
Average UV index in December
Crystal Lake, IA
- Average UV index in December: 1
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Crystal Lake, IA
- Average cloud cover in December: 59
The month with the most cloud cover is January (Cloud cover 63).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in December
Crystal Lake, IA
- Average visibility in December: 5mi
The months with the highest visibility are March, April, May, June, September, October and November (6mi).
The months with the lowest visibility are January, February, July, August and December (5mi).
Crystal Lake, Iowa, USA
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