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
A shift in the average high-temperature occurs in December, reducing from a frosty 49.8°F (9.9°C) in November to an icy 38.5°F (3.6°C). December witnesses an average nighttime temperature of 27.9°F (-2.3°C).Humidity
In December, the average relative humidity in Harristown is 79%.Rainfall
The months with the least rainfall are February and December Rain falls for 7.1 days and accumulates 0.87" (22mm) of rain.Snowfall
January through April, November and December are months with snowfall in Harristown. In Harristown, Illinois, in December, during 5.3 snowfall days, 0.83" (21mm) of snow is typically accumulated. Throughout the year, there are 23.1 snowfall days, and 5.67" (144mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 24min of daylight.On the first day of December, sunrise is at 6:59 am and sunset at 4:32 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:41 pm CST.
Sunshine
In Harristown, the average sunshine in December is 4.6h.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 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: In December, a regular UV index of 2 translates into these guidelines:
Extended exposure to the sun should always be avoided by children, infants, and those with sensitive skin. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage. Be alert to the fact! The reflection from snow can nearly double the UV radiation of the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it cold in Harristown during December?
What is the average humidity in December?
What is the driest month?
How much does it rain in Harristown in December?
How much does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
When is the sunrise / sunset in December?
How many hours of sunshine does Harristown have in December?
When is the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Harristown, IL
- Average high temperature in December: 38.5°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (32.9°F).
- Average low temperature in December: 27.9°F
The month with the highest average low temperature is July (65.7°F).
The coldest month (with the lowest average low temperature) is January (21.2°F).
Average pressure in December
Harristown, IL
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in December
Harristown, IL
- Average wind speed in December: 10.1mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).
Average humidity in December
Harristown, IL
- Average humidity in December: 79%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).
Average rainfall in December
Harristown, IL
- Average rainfall in December: 0.87"
The wettest month (with the highest rainfall) is May (2.01").
The driest months (with the least rainfall) are February and December (0.87").
Average rainfall days in December
Harristown, IL
- Average rainfall days in December: 7.1 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is February (5.8 days).
Average snowfall in December
Harristown, IL
- Average snowfall in December: 0.83"
The month with the highest snowfall is January (1.85").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Harristown, IL
- Average snowfall days in December: 5.3 days
The month with the highest number of snowfall days is January (7.2 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Harristown, 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 24min).
- Average sunshine in December: 4h and 4min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in December
Harristown, IL
- Average sunshine days in December: 19.4 days
The month with the most sunshine days is October (19.8 days).
The month with the least sunshine days is May (11.5 days).
Average UV index in December
Harristown, 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
Harristown, IL
- Average cloud cover in December: 52
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is September (Cloud cover 29).
Average visibility in December
Harristown, 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).
Harristown, Illinois, USA
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