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
Stepping into December, Lerna observes a temperature decline, with the average high falling from November's frosty 49.8°F (9.9°C) to an icy 39°F (3.9°C). The nighttime temperature dips to a subzero cold 28.8°F (-1.8°C) on average during December.Humidity
The average relative humidity in December is 79%.Rainfall
In Lerna, in December, it is raining for 9.4 days, with typically 1.57" (40mm) of accumulated precipitation. In Lerna, during the entire year, the rain falls for 148 days and collects up to 25.63" (651mm) of precipitation.Snowfall
Months with snowfall 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, with an average of 9h and 24min of daylight.On the first day of the month, sunrise is at 6:54 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 December, the average sunshine in Lerna 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 of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV rays for ordinary individuals.Note: A daily high UV index of 1 in December leads to these guidelines:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. Around midday, solar radiation is most harmful; hence, exposure should be limited. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Be vigilant! The reflective nature of snow can increase 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?
How many days does it rain in December?
What is the snowiest month in Lerna?
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 in Lerna?
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?
How high is the UV index in December in Lerna?
Average temperature in December
Lerna, 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
Lerna, 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
Lerna, 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
Lerna, 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
Lerna, 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
Lerna, 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
Lerna, 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
Lerna, 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
Lerna, 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
Lerna, 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
Lerna, 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
Lerna, 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
Lerna, 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).
Lerna, Illinois, USA
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