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 onset of December coincides with a reduction in the average high-temperature, falling from a chilly 43.5°F (6.4°C) in November to a subzero cold 30.2°F (-1°C). During the month of December, Janesville's nighttime temperature lowers to an average of 19.8°F (-6.8°C).Humidity
In Janesville, the average relative humidity in December is 83%.Rainfall
In Janesville, during December, the rain falls for 5.7 days and regularly aggregates up to 1.54" (39mm) of precipitation. In Janesville, Iowa, during the entire year, the rain falls for 138.7 days and collects up to 28.78" (731mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. In Janesville, during December, snow falls for 9.5 days and regularly aggregates up to 3.39" (86mm) of snow. In Janesville, during the entire year, snow falls for 43.6 days and aggregates up to 19.25" (489mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 6min of daylight.On the first day of December, sunrise is at 7:20 am and sunset at 4:37 pm. On the last day of the month, sunrise is at 7:39 am and sunset at 4:46 pm CST.
Sunshine
The average sunshine in December is 4.3h.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 vulnerability from unprotected exposure to Sun's UV rays for average individuals.Note: A maximum UV index of 1 in December translates into the following recommendations:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Be cautious! The UV radiation from the Sun can be magnified almost twofold by snow reflection.
Frequently asked questions
How cold is December in Janesville?
What is the average humidity in December in Janesville?
How many days does it rain in December in Janesville?
How many days does it snow in December in Janesville?
What is the month with the shortest days in Janesville?
How many hours of daylight does Janesville have in December?
What time are sunrise and sunset in December in Janesville?
How many hours of sunshine does Janesville have in December?
What is the month with the lowest UV index in Janesville?
What is the UV index reading in December in Janesville?
Average temperature in December
Janesville, IA
- Average high temperature in December: 30.2°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 (23.9°F).
- Average low temperature in December: 19.8°F
The month with the highest average low temperature is July (63°F).
The coldest month (with the lowest average low temperature) is January (11.3°F).
Average pressure in December
Janesville, IA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in December
Janesville, IA
- Average wind speed in December: 10mph
The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity in December
Janesville, IA
- Average humidity in December: 83%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (72%).
Average rainfall in December
Janesville, IA
- Average rainfall in December: 1.54"
The wettest month (with the highest rainfall) is June (4.29").
The driest month (with the least rainfall) is January (1.02").
Average rainfall days in December
Janesville, IA
- Average rainfall days in December: 5.7 days
The month with the highest number of rainy days is June (19.4 days).
The month with the least rainy days is February (3.9 days).
Average snowfall in December
Janesville, IA
- Average snowfall in December: 3.39"
The month with the highest snowfall is February (5.08").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Janesville, IA
- Average snowfall days in December: 9.5 days
The month with the highest number of snowfall days is January (10.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Janesville, IA
- Average daylight in December: 9h and 1min
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 6min).
- Average sunshine in December: 4h and 2min
The month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days in December
Janesville, IA
- Average sunshine days in December: 17.6 days
The months with the most sunshine days are October and November (17.8 days).
The month with the least sunshine days is June (9.2 days).
Average UV index in December
Janesville, IA
- Average UV index in December: 1
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Janesville, IA
- Average cloud cover in December: 57
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility in December
Janesville, IA
- Average visibility in December: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).
Janesville, Iowa, USA
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