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
December
Weather in December
Temperature
December brings a decrease in the average high-temperature, falling from November's chilly 47.7°F (8.7°C) to a wintry 36.5°F (2.5°C). Washington experiences an average low-temperature of 25.9°F (-3.4°C) in the month of December.Humidity
The average relative humidity in December is 80%.Rainfall
In Washington, in December, it is raining for 6.1 days, with typically 0.98" (25mm) of accumulated precipitation. In Washington, during the entire year, the rain falls for 128.3 days and collects up to 19.13" (486mm) of precipitation.Snowfall
January through April, November and December are months with snowfall in Washington, Illinois. In Washington, Illinois, in December, snow falls for 5.5 days, with typically accumulated 1.18" (30mm) of snow. In Washington, during the entire year, snow falls for 29.2 days and aggregates up to 9.13" (232mm) of snow.Daylight
With an average of 9h and 18min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:02 am and sunset at 4:30 pm. On the last day of December, in Washington, sunrise is at 7:21 am and sunset at 4:40 pm CST.
Sunshine
In Washington, the average sunshine in December is 4.4h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Washington. A UV Index estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for the average person.Note: The average daily UV index of 2 in December transforms into the following instructions:
Although prolonged sun exposure does not typically bother most people, children, babies, and those with sensitive skin should always have protection. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in Washington in December?
What is the average humidity in December in Washington?
How many days does it rain in December in Washington?
How many days does it snow in December in Washington?
What is the month with the shortest days in Washington?
What is the average length of the day in December in Washington?
When are sunrise and sunset in December in Washington?
How many hours of sunshine does Washington have in December?
When is the lowest UV index in Washington?
What is the UV index intensity in December in Washington?
Average temperature in December
Washington, IL
- Average high temperature in December: 36.5°F
The warmest month (with the highest average high temperature) is July (81.5°F).
The month with the lowest average high temperature is January (30.6°F).
- Average low temperature in December: 25.9°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (18.5°F).
Average pressure in December
Washington, IL
- 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 (29.91"Hg).
Average wind speed in December
Washington, IL
- Average wind speed in December: 9.9mph
The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in December
Washington, IL
- Average humidity in December: 80%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Washington, IL
- Average rainfall in December: 0.98"
The wettest month (with the highest rainfall) is May (2.6").
The driest month (with the least rainfall) is November (0.94").
Average rainfall days in December
Washington, IL
- Average rainfall days in December: 6.1 days
The month with the highest number of rainy days is July (16.4 days).
The month with the least rainy days is January (4.4 days).
Average snowfall in December
Washington, IL
- Average snowfall in December: 1.18"
The month with the highest snowfall is January (2.68").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Washington, IL
- Average snowfall days in December: 5.5 days
The month with the highest number of snowfall days is January (10.3 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
Washington, IL
- 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 18min).
- Average sunshine in December: 4h and 2min
The month with the most sunshine is June (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in December
Washington, IL
- Average sunshine days in December: 20.5 days
The month with the most sunshine days is December (20.5 days).
The month with the least sunshine days is July (11.4 days).
Average UV index in December
Washington, IL
- Average UV index in December: 2
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Washington, IL
- Average cloud cover in December: 53
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is September (Cloud cover 30).
Average visibility in December
Washington, 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).