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
As November transitions into December, Rock Island sees a drop in the average high-temperature, transitioning from a frosty 46.8°F (8.2°C) to a wintry 34.3°F (1.3°C). Throughout December, the temperature tends to fall to a consistent average low of 23.7°F (-4.6°C).Humidity
In Rock Island, the average relative humidity in December is 81%.Rainfall
In Rock Island, in December, it is raining for 6.9 days, with typically 1.26" (32mm) of accumulated precipitation. In Rock Island, during the entire year, the rain falls for 138.1 days and collects up to 27.32" (694mm) of precipitation.Snowfall
January through April, October through December are months with snowfall. In Rock Island, in December, snow falls for 6.9 days, with typically accumulated 1.89" (48mm) of snow. In Rock Island, during the entire year, snow falls for 35.5 days and aggregates up to 12.8" (325mm) of snow.Daylight
With an average of 9h and 12min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:09 am and sunset at 4:33 pm. On the last day of December, sunrise is at 7:28 am and sunset at 4:42 pm CST.
Sunshine
The average sunshine in December in Rock Island is 4.2h.UV index
In Rock Island, Illinois, the average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a low health risk from exposure to the Sun's UV rays for ordinary individuals.Note: The maximum UV index of 2 during December translates into these guidelines:
Apart from children, who require continuous protection, most can endure sun exposure for up to an hour without experiencing burns. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Remember this! The UV radiation of the Sun can be nearly doubled by the reflective properties of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in December?
What is the average humidity in December?
How much does it rain in December?
How much does it snow in December?
What is the month with the shortest days in Rock Island?
What is the average length of the day in December?
When is the sunrise / sunset in December?
How many hours of sunshine does Rock Island have in December?
What is the UV index intensity in December?
Average temperature in December
Rock Island, IL
- Average high temperature in December: 34.3°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (28°F).
- Average low temperature in December: 23.7°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (15.6°F).
Average pressure in December
Rock Island, IL
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in December
Rock Island, IL
- Average wind speed in December: 9.8mph
The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.7mph).
Average humidity in December
Rock Island, IL
- Average humidity in December: 81%
The months with the highest relative humidity are January and July (83%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Rock Island, IL
- Average rainfall in December: 1.26"
The wettest month (with the highest rainfall) is May (4.49").
The driest month (with the least rainfall) is February (1.1").
Average rainfall days in December
Rock Island, IL
- Average rainfall days in December: 6.9 days
The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is January (4.3 days).
Average snowfall in December
Rock Island, IL
- Average snowfall in December: 1.89"
The month with the highest snowfall is January (3.98").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Rock Island, IL
- Average snowfall days in December: 6.9 days
The month with the highest number of snowfall days is January (10.9 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
Rock Island, IL
- Average daylight in December: 9h and 1min
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 12min).
- Average sunshine in December: 4h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in December
Rock Island, IL
- Average sunshine days in December: 17.8 days
The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is May (11.4 days).
Average UV index in December
Rock Island, IL
- Average UV index in December: 2
The months with the highest UV index are July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in December
Rock Island, IL
- Average cloud cover in December: 55
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in December
Rock Island, 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).
Rock Island, Illinois, USA
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