December weather forecastByron, IL
December
Weather in December
December, the first month of the winter in Byron, is also a wintry month, with an average temperature fluctuating between 32.5°F (0.3°C) and 22.5°F (-5.3°C).Temperature
The commencement of December involves a temperature shift, with the average high-temperature dropping from a chilly 44.8°F (7.1°C) in November to a cold 32.5°F (0.3°C). Byron, in December, observes a steady average low-temperature of 22.5°F (-5.3°C).Humidity
In Byron, the average relative humidity in December is 83%.Rainfall
In Byron, in December, it is raining for 4.6 days, with typically 0.39" (10mm) of accumulated precipitation. Throughout the year, there are 100.6 rainfall days, and 7.99" (203mm) of precipitation is accumulated.Snowfall
January through April, October through December are months with snowfall. In Byron, during December, snow falls for 6.6 days and regularly aggregates up to 0.35" (9mm) of snow. In Byron, during the entire year, snow falls for 29.5 days and aggregates up to 3.66" (93mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 12min of daylight.On the first day of the month, sunrise is at 7:06 am and sunset at 4:26 pm. On the last day of December, sunrise is at 7:25 am and sunset at 4:35 pm CST.
Sunshine
In December, the average sunshine is 3.9h.UV index
January and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV rays for average individuals.Note: In December, a regular UV index of 1 translates into these guidelines:
Babies, children, and those with sensitive skin should always avoid extended periods in the sun. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears. Foresee this! The reflection from snow can nearly double the intensity of UV radiation from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Byron, IL
- Average high temperature in December: 32.5°F
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (26.2°F).
- Average low temperature in December: 22.5°F
The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is January (14°F).
Average pressure in December
Byron, IL
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Byron, IL
- Average wind speed in December: 9.4mph
The windiest month (with the highest average wind speed) is April (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).
Average humidity in December
Byron, IL
- Average humidity in December: 83%
The month with the highest relative humidity is January (86%).
The months with the lowest relative humidity are April and October (75%).
Average rainfall in December
Byron, IL
- Average rainfall in December: 0.39"
The wettest month (with the highest rainfall) is May (1.18").
The driest months (with the least rainfall) are January and February (0.35").
Average rainfall days in December
Byron, IL
- Average rainfall days in December: 4.6 days
The month with the highest number of rainy days is May (13.8 days).
The month with the least rainy days is January (3.2 days).
Average snowfall in December
Byron, IL
- Average snowfall in December: 0.35"
The month with the highest snowfall is January (1.42").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Byron, IL
- Average snowfall days in December: 6.6 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
Byron, IL
- Average daylight in December: 9h and 12min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in December: 3h and 54min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in December
Byron, IL
- Average sunshine days in December: 22.6 days
The month with the most sunshine days is December (22.6 days).
The month with the least sunshine days is June (12.8 days).
Average UV index in December
Byron, IL
- Average UV index in December: 1
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Byron, IL
- Average cloud cover in December: 59
The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is September (Cloud cover 33).
Average visibility in December
Byron, IL
- Average visibility in December: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).





