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
In December, the average high-temperature goes from a chilly 49.8°F (9.9°C) in November to a wintry 39°F (3.9°C). December in Mattoon witnesses an average low-temperature hovering around a freezing cold 28.8°F (-1.8°C).Humidity
In December, the average relative humidity is 79%.Rainfall
In Mattoon, during December, the rain falls for 9.4 days and regularly aggregates up to 1.57" (40mm) of precipitation. In Mattoon, during the entire year, the rain falls for 148 days and collects up to 25.63" (651mm) of precipitation.Snowfall
Months with snowfall in Mattoon are January through April, October through December. The month with the most snowfall is December, when snow falls for 6 days and typically aggregates up to 2.13" (54mm) of snow.Daylight
December has the shortest days of the year in Mattoon, 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, in Mattoon, Illinois, sunrise is at 7:13 am and sunset at 4:39 pm CST.
Sunshine
In December, the average sunshine in Mattoon is 4.4h.UV index
December is the month with the lowest UV index, with an average maximum UV index of 1. A UV Index reading of 2, and below, represents a low health risk from exposure to the Sun's UV radiation for average individuals.Note: A daily maximum UV index of 1 in December translates into the following instructions:
Long-term sun exposure is typically not a concern for most. However, those with sensitive skin, infants, and children must always have protection. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Experience reduced UV exposure by about half when donning a wide-brim hat. Be cautious! The UV radiation from the Sun can be magnified almost twofold by snow reflection.
Frequently asked questions
How cold is it in Mattoon in December?
What is the average humidity in December in Mattoon?
How much does it rain in Mattoon in December?
When does it snow the most in Mattoon?
How many days does it snow in December in Mattoon?
What is the month with the shortest days in Mattoon?
What is the average length of the day in December in Mattoon?
When are sunrise and sunset in December in Mattoon?
How many hours of sunshine does Mattoon have in December?
What is the month with the lowest UV index in Mattoon?
What is the UV index reading in December in Mattoon?
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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