December weather forecastChatham, IL
December
Weather in December
The first month of the winter, December, is still a cold month in Chatham, Illinois, with an average temperature varying between 38.8°F (3.8°C) and 28.4°F (-2°C).Temperature
The shift from November to December involves a decrease in the average high-temperature, from a fresh 50.2°F (10.1°C) to a cold 38.8°F (3.8°C). Chatham witnesses a consistent average low-temperature of 28.4°F (-2°C) throughout December.Humidity
The average relative humidity in December is 78%.Rainfall
The month with the least rainfall is December, when the rain falls for 5.5 days and typically collects 0.43" (11mm) of precipitation.Snowfall
January through April, November and December are months with snowfall. In Chatham, in December, during 3.9 snowfall days, 0.47" (12mm) of snow is typically accumulated. Throughout the year, there are 18.6 snowfall days, and 2.68" (68mm) of snow is accumulated.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 7:01 am and sunset at 4:35 pm. On the last day of December, sunrise is at 7:19 am and sunset at 4:44 pm CST.
Sunshine
The average sunshine in December is 4.8h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for the average person.Note: In December, a regular UV index of 2 translates into these guidelines:
Protection from prolonged sun exposure is necessary for babies, children, and individuals with sensitive skin. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. Take heed! Reflection from the snow can almost amplify the Sun's UV radiation by double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Chatham, IL
- Average high temperature in December: 38.8°F
The warmest month (with the highest average high temperature) is July (82.8°F).
The month with the lowest average high temperature is January (33.6°F).
- Average low temperature in December: 28.4°F
The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (21.4°F).
Average pressure in December
Chatham, 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 (29.91"Hg).
Average wind speed in December
Chatham, IL
- Average wind speed in December: 9.8mph
The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest month (with the lowest average wind speed) is July (6.1mph).
Average humidity in December
Chatham, IL
- Average humidity in December: 78%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall in December
Chatham, IL
- Average rainfall in December: 0.43"
The wettest month (with the highest rainfall) is June (1.22").
The driest month (with the least rainfall) is December (0.43").
Average rainfall days in December
Chatham, IL
- Average rainfall days in December: 5.5 days
The month with the highest number of rainy days is May (12.5 days).
The month with the least rainy days is January (4.4 days).
Average snowfall in December
Chatham, IL
- Average snowfall in December: 0.47"
The month with the highest snowfall is February (0.91").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Chatham, IL
- Average snowfall days in December: 3.9 days
The month with the highest number of snowfall days is January (5.7 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
Chatham, IL
- Average daylight in December: 9h and 24min
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 48min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in December
Chatham, 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 (14 days).
Average UV index in December
Chatham, 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
Chatham, IL
- Average cloud cover in December: 50
The month with the most cloud cover is January (Cloud cover 54).
The months with the least cloud cover are June and September (Cloud cover 29).
Average visibility in December
Chatham, 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).
