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 ushers in a slight temperature change, with average high-temperatures reducing from November's chilly 46.9°F (8.3°C) to a wintry 34.5°F (1.4°C). In the month of December, the average low-temperature usually rests at a subzero cold 23.9°F (-4.5°C).Humidity
In Port Byron, the average relative humidity in December is 81%.Rainfall
December is the month with the least rainfall in Port Byron. Rain falls for 4.1 days and accumulates 0.35" (9mm) of precipitation.Snowfall
January through April, September through December are months with snowfall in Port Byron. In Port Byron, in December, during 5 snowfall days, 0.39" (10mm) of snow is typically accumulated. Throughout the year, in Port Byron, there are 24.5 snowfall days, and 4.09" (104mm) of snow is accumulated.Daylight
December has the shortest days of the year in Port Byron, with an average of 9h and 12min of daylight.On the first day of the month, sunrise is at 7:09 am and sunset at 4:31 pm. On the last day of December, in Port Byron, sunrise is at 7:27 am and sunset at 4:41 pm CST.
Sunshine
In Port Byron, Illinois, the average sunshine in December is 4.2h.UV index
In December, the average daily maximum UV index is 2. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV rays for average individuals.Note: In December, the maximum UV index of 2 translates into these guidelines:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly. Beware! Reflection from snow can magnify the Sun's UV radiation nearly twofold.
Frequently asked questions
How cold is it in Port Byron in December?
What is the average humidity in December in Port Byron?
What is the driest month in Port Byron?
How much does it rain in Port Byron in December?
How much does it snow in Port Byron in December?
What is the month with the shortest days in Port Byron?
How many hours of daylight does Port Byron have in December?
When are sunrise and sunset in December in Port Byron?
How many hours of sunshine does Port Byron have in December?
What is the UV index reading in December in Port Byron?
Average temperature in December
Port Byron, IL
- Average high temperature in December: 34.5°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (28.2°F).
- Average low temperature in December: 23.9°F
The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (15.4°F).
Average pressure in December
Port Byron, IL
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Port Byron, IL
- Average wind speed in December: 9.8mph
The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.7mph).
Average humidity in December
Port Byron, IL
- Average humidity in December: 81%
The months with the highest relative humidity are January and July (83%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Port Byron, IL
- Average rainfall in December: 0.35"
The wettest month (with the highest rainfall) is May (1.61").
The driest month (with the least rainfall) is December (0.35").
Average rainfall days in December
Port Byron, IL
- Average rainfall days in December: 4.1 days
The month with the highest number of rainy days is May (13.4 days).
The month with the least rainy days is January (3.2 days).
Average snowfall in December
Port Byron, IL
- Average snowfall in December: 0.39"
The month with the highest snowfall is January (1.26").
The months with the least snowfall are May, June, July and August (0").
Average snowfall days in December
Port Byron, IL
- Average snowfall days in December: 5 days
The month with the highest number of snowfall days is January (7.2 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in December /
Average sunshine in December
Port Byron, IL
- Average daylight in December: 9h and 1min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in December: 4h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in December
Port Byron, IL
- Average sunshine days in December: 22.4 days
The month with the most sunshine days is December (22.4 days).
The month with the least sunshine days is June (14.4 days).
Average UV index in December
Port Byron, IL
- Average UV index in December: 2
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in December
Port Byron, IL
- Average cloud cover in December: 56
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in December
Port Byron, IL
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Port Byron, Illinois, USA
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