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
December tends to be the coldest month, with temperatures averaging a daily high of 36.9°F (2.7°C) and a low of 22.6°F (-5.2°C).Humidity
The average relative humidity in December in Janesville is 78%.Rainfall
December is the month with the most rainfall in Janesville. Rain falls for 10.8 days and accumulates 2.28" (58mm) of precipitation.Snowfall
Months with snowfall in Janesville are January through June, September through December. The month with the most snowfall is December, when snow falls for 11.4 days and typically aggregates up to 10.16" (258mm) of snow.Daylight
December has the shortest days of the year in Janesville, California, with an average of 9h and 24min of daylight.On the first day of the month, sunrise is at 7:06 am and sunset at 4:36 pm. On the last day of December, sunrise is at 7:24 am and sunset at 4:46 pm PST.
Sunshine
January and December, with an average of 5.8h of sunshine, are months with the least sunshine.UV index
In Janesville, the average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a low health risk from exposure to the Sun's UV rays for the average person.Note: An average maximum UV index of 2 in December leads to these recommendations:
Despite most people tolerating extended sun exposure, it is critical to always protect those with sensitive skin, infants, and children. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Frequently asked questions
What time of the year is the coldest in Janesville?
How cold is December in Janesville?
What is the average humidity in December in Janesville?
What is the rainiest month in Janesville?
How many days does it rain in December in Janesville?
When does it snow the most in Janesville?
How much does it snow in Janesville in December?
What is the month with the shortest days in Janesville?
What is the average length of the day in December in Janesville?
What time are sunrise and sunset in December in Janesville?
What is the month with the least sunshine in Janesville?
How long on average sun shines in December in Janesville?
What is the UV index reading in December in Janesville?
Average temperature in December
Janesville, CA
- Average high temperature in December: 36.9°F
The warmest month (with the highest average high temperature) is July (84.6°F).
The month with the lowest average high temperature is December (36.9°F).
- Average low temperature in December: 22.6°F
The month with the highest average low temperature is July (52.7°F).
The coldest month (with the lowest average low temperature) is December (22.6°F).
Average pressure in December
Janesville, CA
- Average pressure in December: 30.17"Hg
The month with the highest atmospheric pressure is January (30.2"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in December
Janesville, CA
- Average wind speed in December: 5.5mph
The windiest month (with the highest average wind speed) is April (7.2mph).
The calmest month (with the lowest average wind speed) is January (5.2mph).
Average humidity in December
Janesville, CA
- Average humidity in December: 78%
The month with the highest relative humidity is January (81%).
The months with the lowest relative humidity are July and August (35%).
Average rainfall in December
Janesville, CA
- Average rainfall in December: 2.28"
The wettest month (with the highest rainfall) is December (2.28").
The driest month (with the least rainfall) is July (0.12").
Average rainfall days in December
Janesville, CA
- Average rainfall days in December: 10.8 days
The month with the highest number of rainy days is March (13.4 days).
The months with the least rainy days are July and August (2.8 days).
Average snowfall in December
Janesville, CA
- Average snowfall in December: 10.16"
The month with the highest snowfall is December (10.16").
The months with the least snowfall are July and August (0").
Average snowfall days in December
Janesville, CA
- Average snowfall days in December: 11.4 days
The month with the highest number of snowfall days is December (11.4 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in December /
Average sunshine in December
Janesville, CA
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in December: 5h and 5min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are January and December (Average sunshine: 5h and 48min).
Average sunshine days in December
Janesville, CA
- Average sunshine days in December: 14.5 days
The month with the most sunshine days is August (26.2 days).
The month with the least sunshine days is March (12 days).
Average UV index in December
Janesville, CA
- Average UV index in December: 2
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are February and November (UV index 1).
Average cloud cover in December
Janesville, CA
- Average cloud cover in December: 38
The month with the most cloud cover is December (Cloud cover 38).
The months with the least cloud cover are July and August (Cloud cover 7).
Average visibility in December
Janesville, CA
- Average visibility in December: 5mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (5mi).
Janesville, California, USA
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