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
With the onset of December, Mattoon experiences a modest temperature adjustment, with the average high-temperature receding from a frosty 49.8°F (9.9°C) in November to a wintry 39°F (3.9°C). An average low-temperature of 28.8°F (-1.8°C) is anticipated throughout the nights during December.Humidity
In December, the average relative humidity in Mattoon is 79%.Rainfall
In Mattoon, in December, it is raining for 9.4 days, with typically 1.57" (40mm) of accumulated precipitation. Throughout the year, there are 148 rainfall days, and 25.63" (651mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, October through December. December is the month with the most snowfall in Mattoon. Snow falls for 6 days and accumulates 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 6:55 am and sunset at 4:30 pm. On the last day of December, sunrise is at 7:13 am and sunset at 4:39 pm CST.
Sunshine
In Mattoon, 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. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: A maximum high UV index of 1 in December translates into the following recommendations:
Sun exposure does not present considerable issues for many, yet infants, fair-skinned people, and children necessitate constant protection. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days. Pay attention! The reflection of snow can enhance the Sun's UV radiation almost double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is December cold?
What is the average humidity in December?
How much does it rain in December?
What is the snowiest month?
How many days does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Mattoon have in December?
What time are sunrise and sunset in December?
How long on average sun shines in December?
What is the month with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Mattoon, 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
Mattoon, 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
Mattoon, 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
Mattoon, 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
Mattoon, 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
Mattoon, 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
Mattoon, 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
Mattoon, 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
Mattoon, 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
Mattoon, 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
Mattoon, 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
Mattoon, 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
Mattoon, 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).
Mattoon, Illinois, USA
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