December weather forecastSeneca, IL
December
Weather in December
December, the first month of the winter in Seneca, is still a cold month, with an average temperature varying between 35.1°F (1.7°C) and 25.2°F (-3.8°C).Temperature
Welcoming December, Seneca observes a shift in the average high-temperature, falling from November's chilly 47.1°F (8.4°C) to an icy 35.1°F (1.7°C). Seneca's average low-temperature for the month of December records at a freezing cold 25.2°F (-3.8°C).Humidity
In December, the average relative humidity is 82%.Rainfall
The month with the least rainfall in Seneca is December, when the rain falls for 7.6 days and typically collects 1.65" (42mm) of precipitation.Snowfall
January through April, October through December are months with snowfall in Seneca. In Seneca, in December, snow falls for 8.2 days, with typically accumulated 2.52" (64mm) of snow. Throughout the year, in Seneca, Illinois, there are 39.8 snowfall days, and 15.71" (399mm) of snow is accumulated.Daylight
The month with the shortest days in Seneca, Illinois, is December, with an average of 9h and 18min of daylight.On the first day of the month, sunrise is at 7:01 am and sunset at 4:25 pm. On the last day of December, in Seneca, sunrise is at 7:20 am and sunset at 4:35 pm CST.
Sunshine
In Seneca, Illinois, the average sunshine in December is 4.3h.UV index
In December, the average daily maximum UV index in Seneca is 2. A UV Index estimate of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for the ordinary person.Note: The average daily UV index of 2 in December transforms into the following instructions:
Most people face no serious problems with extended sun exposure, but those with fair skin, infants, and children always need protection. It's recommended to limit sun exposure when its radiation is at its peak during midday. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance. 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
Seneca, IL
- Average high temperature in December: 35.1°F
The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (29.1°F).
- Average low temperature in December: 25.2°F
The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (17.2°F).
Average pressure in December
Seneca, 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 (29.92"Hg).
Average wind speed in December
Seneca, IL
- Average wind speed in December: 9.5mph
The windiest months (with the highest average wind speed) are January and April (10.1mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).
Average humidity in December
Seneca, IL
- Average humidity in December: 82%
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (72%).
Average rainfall in December
Seneca, IL
- Average rainfall in December: 1.65"
The wettest month (with the highest rainfall) is May (4.49").
The driest month (with the least rainfall) is December (1.65").
Average rainfall days in December
Seneca, IL
- Average rainfall days in December: 7.6 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is February (5.8 days).
Average snowfall in December
Seneca, IL
- Average snowfall in December: 2.52"
The month with the highest snowfall is February (4.57").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Seneca, IL
- Average snowfall days in December: 8.2 days
The month with the highest number of snowfall days is January (11.9 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
Seneca, IL
- Average daylight in December: 9h and 18min
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 18min).
- Average sunshine in December: 4h and 18min
The months with the most sunshine are June and August (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in December
Seneca, IL
- Average sunshine days in December: 16.5 days
The month with the most sunshine days is November (17.1 days).
The month with the least sunshine days is June (10.1 days).
Average UV index in December
Seneca, IL
- Average UV index in December: 2
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in December
Seneca, IL
- Average cloud cover in December: 55
The month with the most cloud cover is January (Cloud cover 59).
The month with the least cloud cover is September (Cloud cover 32).
Average visibility in December
Seneca, 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).
