December weather forecastPlymouth, IL
December
Weather in December
December, the first month of the winter in Plymouth, is still a cold month, with an average temperature fluctuating between 25.9°F (-3.4°C) and 37°F (2.8°C).Temperature
As Plymouth enters December, the average high-temperature decreases from the a chilly 49.1°F (9.5°C) of November to a wintry 37°F (2.8°C). Throughout the December nights, Plymouth encounters a low-temperature of 25.9°F (-3.4°C).Humidity
The average relative humidity in December is 79%.Rainfall
The month with the least rainfall in Plymouth is December, when the rain falls for 4.3 days and typically collects 0.35" (9mm) of precipitation.Snowfall
Months with snowfall are January through April, October through December. In December, it is snowing for 3.7 days. Throughout December, 0.24" (6mm) of snow is accumulated. In Plymouth, during the entire year, snow falls for 20.5 days and aggregates up to 2.44" (62mm) of snow.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year in Plymouth.On the first day of the month, sunrise is at 7:07 am and sunset at 4:38 pm. On the last day of December, sunrise is at 7:26 am and sunset at 4:47 pm CST.
Sunshine
The average sunshine in December in Plymouth is 4.6h.UV index
In Plymouth, the average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV radiation for average individuals.Note: An average maximum UV index of 2 in December leads to these recommendations:
Those with sensitive skin, infants, and children require constant safeguarding from prolonged sun exposure. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Be informed! The Sun's UV radiation can be nearly doubled due to the reflection from snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Plymouth, IL
- Average high temperature in December: 37°F
The warmest month (with the highest average high temperature) is July (82.6°F).
The month with the lowest average high temperature is January (31.1°F).
- Average low temperature in December: 25.9°F
The month with the highest average low temperature is July (66.2°F).
The coldest month (with the lowest average low temperature) is January (19°F).
Average pressure in December
Plymouth, IL
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in December
Plymouth, IL
- Average wind speed in December: 9.9mph
The windiest month (with the highest average wind speed) is January (10.5mph).
The calmest months (with the lowest average wind speed) are July and August (6.6mph).
Average humidity in December
Plymouth, 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 (71%).
Average rainfall in December
Plymouth, IL
- Average rainfall in December: 0.35"
The wettest month (with the highest rainfall) is May (1.1").
The driest month (with the least rainfall) is December (0.35").
Average rainfall days in December
Plymouth, IL
- Average rainfall days in December: 4.3 days
The month with the highest number of rainy days is May (12.3 days).
The month with the least rainy days is January (3.3 days).
Average snowfall in December
Plymouth, IL
- Average snowfall in December: 0.24"
The month with the highest snowfall is January (0.67").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Plymouth, IL
- Average snowfall days in December: 3.7 days
The month with the highest number of snowfall days is January (6.3 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
Plymouth, IL
- Average daylight in December: 9h and 24min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in December: 4h and 36min
The months with the most sunshine are June and July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in December
Plymouth, IL
- Average sunshine days in December: 23.5 days
The month with the most sunshine days is December (23.5 days).
The month with the least sunshine days is June (13.9 days).
Average UV index in December
Plymouth, IL
- Average UV index in December: 2
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in December
Plymouth, IL
- Average cloud cover in December: 51
The month with the most cloud cover is January (Cloud cover 55).
The month with the least cloud cover is August (Cloud cover 29).
Average visibility in December
Plymouth, 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).





