December weather forecastMcHenry, IL
December
Weather in December
The first month of the winter, December, is also a wintry month in McHenry, Illinois, with an average temperature varying between 32.7°F (0.4°C) and 22.8°F (-5.1°C).Temperature
The average high-temperature decreases in December, shifting from a frosty 44.6°F (7°C) in November to a wintry 32.7°F (0.4°C). Throughout the month of December, McHenry sees a steady low-temperature average of 22.8°F (-5.1°C).Humidity
In December, the average relative humidity is 82%.Rainfall
December is the month with the least rainfall. Rain falls for 7.9 days and accumulates 1.34" (34mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In December, it is snowing for 10.3 days. Throughout December, 2.6" (66mm) of snow is accumulated. In McHenry, during the entire year, snow falls for 49 days and aggregates up to 16.5" (419mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 6min of daylight.On the first day of the month, sunrise is at 7:03 am and sunset at 4:21 pm. On the last day of December, sunrise is at 7:22 am and sunset at 4:30 pm CST.
Sunshine
In December, the average sunshine is 4h.UV index
The months with the lowest UV index in McHenry are January and December, with an average maximum UV index of 1. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV rays for average individuals.Note: In December, the maximum UV index of 1 translates into these guidelines:
Most individuals can handle sun exposure for up to an hour without burning, but children must always be shielded from sun exposure. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Take note! UV radiation from the Sun can double in intensity due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
McHenry, IL
- Average high temperature in December: 32.7°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (26.6°F).
- Average low temperature in December: 22.8°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 (14.9°F).
Average pressure in December
McHenry, IL
- Average pressure in December: 30.09"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in December
McHenry, IL
- Average wind speed in December: 9.3mph
The windiest month (with the highest average wind speed) is January (10mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).
Average humidity in December
McHenry, IL
- Average humidity in December: 82%
The months with the highest relative humidity are January and February (85%).
The month with the lowest relative humidity is October (76%).
Average rainfall in December
McHenry, IL
- Average rainfall in December: 1.34"
The wettest month (with the highest rainfall) is June (3.58").
The driest month (with the least rainfall) is December (1.34").
Average rainfall days in December
McHenry, IL
- Average rainfall days in December: 7.9 days
The month with the highest number of rainy days is July (18.3 days).
The month with the least rainy days is February (4.9 days).
Average snowfall in December
McHenry, IL
- Average snowfall in December: 2.6"
The month with the highest snowfall is January (5.16").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
McHenry, IL
- Average snowfall days in December: 10.3 days
The month with the highest number of snowfall days is January (13.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
McHenry, IL
- Average daylight in December: 9h and 6min
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 6min).
- Average sunshine in December: 4h and 0min
The months with the most sunshine are July and August (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in December
McHenry, IL
- Average sunshine days in December: 15.9 days
The month with the most sunshine days is November (16 days).
The month with the least sunshine days is June (10.2 days).
Average UV index in December
McHenry, IL
- Average UV index in December: 1
The month with the highest UV index is August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
McHenry, IL
- Average cloud cover in December: 60
The month with the most cloud cover is January (Cloud cover 62).
The months with the least cloud cover are August and September (Cloud cover 31).
Average visibility in December
McHenry, IL
- Average visibility in December: 6mi
The months with the highest visibility are March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January and February (5mi).
