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
As December commences, the average high-temperature shows a reduction, transitioning from a chilly 49.8°F (9.9°C) in November to a wintry 39°F (3.9°C). Janesville in December anticipates an average nighttime temperature of 28.8°F (-1.8°C).Humidity
The average relative humidity in December in Janesville, Illinois, is 79%.Rainfall
In Janesville, during December, the rain falls for 9.4 days and regularly aggregates up to 1.57" (40mm) of precipitation. In Janesville, Illinois, during the entire year, the rain falls for 148 days and collects up to 25.63" (651mm) of precipitation.Snowfall
Months with snowfall in Janesville are January through April, October through December. The month with the most snowfall is December, when snow falls for 6 days and typically aggregates up to 2.13" (54mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 24min of daylight.On the first day of the month, sunrise is at 6:54 am and sunset at 4:30 pm. On the last day of December, in Janesville, sunrise is at 7:12 am and sunset at 4:39 pm CST.
Sunshine
In Janesville, Illinois, the average sunshine in December is 4.4h.UV index
With an average maximum UV index of 1, December is the month with the lowest UV index in Janesville. A UV Index estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for average individuals.Note: The daily maximum UV index of 1 in December interprets into the following advice:
Despite the majority tolerating prolonged sun exposure, those with sensitive skin, infants, and children demand continual protection. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Experience reduced UV exposure by about half when donning a wide-brim hat. Guard yourself! Snow reflection can almost double the UV radiation from the Sun.
Frequently asked questions
Is December cold in Janesville?
What is the average humidity in December in Janesville?
How many days does it rain in December in Janesville?
When does it snow the most in Janesville?
How many days does it snow in December in Janesville?
What is the month with the shortest days in Janesville?
What is the average length of the day in December in Janesville?
When is the sunrise / sunset in December in Janesville?
How many hours of sunshine does Janesville have in December?
When is the lowest UV index in Janesville?
How high is the UV index in December in Janesville?
Average temperature in December
Janesville, IL
- Average high temperature in December: 39°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (34°F).
- Average low temperature in December: 28.8°F
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (21.9°F).
Average pressure in December
Janesville, IL
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in December
Janesville, IL
- Average wind speed in December: 9.9mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest month (with the lowest average wind speed) is July (6.2mph).
Average humidity in December
Janesville, IL
- Average humidity in December: 79%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall in December
Janesville, IL
- Average rainfall in December: 1.57"
The wettest month (with the highest rainfall) is April (3.31").
The driest month (with the least rainfall) is February (1.3").
Average rainfall days in December
Janesville, IL
- Average rainfall days in December: 9.4 days
The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is February (7.8 days).
Average snowfall in December
Janesville, IL
- Average snowfall in December: 2.13"
The month with the highest snowfall is December (2.13").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Janesville, IL
- Average snowfall days in December: 6 days
The month with the highest number of snowfall days is January (8.1 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
Janesville, IL
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in December: 4h and 2min
The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in December
Janesville, IL
- Average sunshine days in December: 16.9 days
The month with the most sunshine days is October (18.3 days).
The month with the least sunshine days is July (10.6 days).
Average UV index in December
Janesville, 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
Janesville, IL
- Average cloud cover in December: 54
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is June (Cloud cover 31).
Average visibility in December
Janesville, IL
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
Janesville, Illinois, USA
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