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
The onset of December introduces a moderate change in Harrisburg's weather, with average high-temperatures falling from November's fresh 53.8°F (12.1°C) to a chilly 44.1°F (6.7°C). Harrisburg, in December, witnesses an average low-temperature of 32.4°F (0.2°C).Humidity
In December, the average relative humidity is 78%.Rainfall
In December, the rain falls for 10.3 days. Throughout December, 2.8" (71mm) of precipitation is accumulated. Throughout the year, there are 158.6 rainfall days, and 36.02" (915mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, October through December. In Harrisburg, in December, during 3.6 snowfall days, 1.18" (30mm) of snow is typically accumulated. In Harrisburg, during the entire year, snow falls for 17.7 days and aggregates up to 6.57" (167mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 36min of daylight.On the first day of the month, sunrise is at 6:51 am and sunset at 4:35 pm. On the last day of December, sunrise is at 7:09 am and sunset at 4:45 pm CST.
Sunshine
In December, the average sunshine is 4.7h.UV index
January, February 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 minimal health hazard from exposure to the Sun's UV radiation for the ordinary person.Note: In December, the maximum UV index of 2 suggests this advice:
Infants, children, and people with sensitive skin should always have protection against lengthy periods of sun exposure. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Note well! The intensity of the Sun's UV rays can be nearly doubled by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it cold during December?
What is the average humidity in December?
How many days does it rain in December in Harrisburg?
How much does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
When are sunrise and sunset in December?
How long on average sun shines in December?
When is the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Harrisburg, IL
- Average high temperature in December: 44.1°F
The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (39.7°F).
- Average low temperature in December: 32.4°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (26.2°F).
Average pressure in December
Harrisburg, IL
- Average pressure in December: 30.14"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in December
Harrisburg, IL
- Average wind speed in December: 8.8mph
The windiest months (with the highest average wind speed) are January and February (9.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).
Average humidity in December
Harrisburg, IL
- Average humidity in December: 78%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (70%).
Average rainfall in December
Harrisburg, IL
- Average rainfall in December: 2.8"
The wettest month (with the highest rainfall) is April (4.8").
The driest month (with the least rainfall) is September (1.57").
Average rainfall days in December
Harrisburg, IL
- Average rainfall days in December: 10.3 days
The month with the highest number of rainy days is May (18.5 days).
The month with the least rainy days is November (9.7 days).
Average snowfall in December
Harrisburg, IL
- Average snowfall in December: 1.18"
The month with the highest snowfall is January (1.73").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Harrisburg, IL
- Average snowfall days in December: 3.6 days
The month with the highest number of snowfall days is January (5.3 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
Harrisburg, IL
- Average daylight in December: 9h and 4min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in December: 4h and 4min
The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).
Average sunshine days in December
Harrisburg, IL
- Average sunshine days in December: 16.9 days
The month with the most sunshine days is October (19.5 days).
The month with the least sunshine days is May (9.9 days).
Average UV index in December
Harrisburg, IL
- Average UV index in December: 2
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).
Average cloud cover in December
Harrisburg, IL
- Average cloud cover in December: 50
The months with the most cloud cover are January and February (Cloud cover 51).
The months with the least cloud cover are June and September (Cloud cover 28).
Average visibility in December
Harrisburg, 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).
Harrisburg, Illinois, USA
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