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 brings a minor decrease, with the average high-temperature reducing from a chilly 49.1°F (9.5°C) in November to a cold 37.9°F (3.3°C). Nighttime temperatures hover around an average low of 27.5°F (-2.5°C) in December.Humidity
In Monticello, the average relative humidity in December is 79%.Rainfall
December is the month with the least rainfall. Rain falls for 7.4 days and accumulates 0.91" (23mm) of precipitation.Snowfall
January through April, November and December are months with snowfall. In Monticello, in December, snow falls for 4.5 days, with typically accumulated 0.79" (20mm) of snow. In Monticello, during the entire year, snow falls for 23.2 days and aggregates up to 5.83" (148mm) of snow.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 6:57 am and sunset at 4:29 pm. On the last day of December, sunrise is at 7:16 am and sunset at 4:39 pm CST.
Sunshine
The average sunshine in December is 4.4h.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 reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for the ordinary person.Note: An average UV index of 2 in December transforms into this advice:
While extended sun exposure does not significantly affect most people, those with sensitive skin, children, and infants should always be protected. For skin protection, it's recommended to minimize Sun exposure during its peak hours around midday. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Beware! Reflection from snow can magnify the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What is the average humidity in December?
What is the driest month?
How many days does it rain in December in Monticello?
How much does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Monticello have in December?
When is the sunrise / sunset in December?
How many hours of sunshine does Monticello have in December?
When is the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Monticello, IL
- Average high temperature in December: 37.9°F
The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (32.4°F).
- Average low temperature in December: 27.5°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 (20.3°F).
Average pressure in December
Monticello, IL
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in December
Monticello, IL
- Average wind speed in December: 10.2mph
The windiest month (with the highest average wind speed) is January (10.9mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).
Average humidity in December
Monticello, IL
- Average humidity in December: 79%
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (70%).
Average rainfall in December
Monticello, IL
- Average rainfall in December: 0.91"
The wettest month (with the highest rainfall) is May (2.09").
The driest month (with the least rainfall) is December (0.91").
Average rainfall days in December
Monticello, IL
- Average rainfall days in December: 7.4 days
The month with the highest number of rainy days is May (16.3 days).
The month with the least rainy days is February (5.2 days).
Average snowfall in December
Monticello, IL
- Average snowfall in December: 0.79"
The month with the highest snowfall is January (2.05").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Monticello, IL
- Average snowfall days in December: 4.5 days
The month with the highest number of snowfall days is January (8.3 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
Monticello, 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 2min
The month with the most sunshine is June (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in December
Monticello, IL
- Average sunshine days in December: 19.1 days
The month with the most sunshine days is November (19.6 days).
The month with the least sunshine days is May (12.3 days).
Average UV index in December
Monticello, 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
Monticello, IL
- Average cloud cover in December: 54
The month with the most cloud cover is January (Cloud cover 57).
The months with the least cloud cover are June, August and September (Cloud cover 32).
Average visibility in December
Monticello, 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).
Monticello, Illinois, USA
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