December weather forecastRock Falls, IA
December
Weather in December
December, the first month of the winter in Rock Falls, is also a subzero cold month, with an average temperature varying between 18°F (-7.8°C) and 28.4°F (-2°C).Temperature
In Rock Falls, the onset of December is marked by a decreased average high-temperature, declining from November's frosty 42.8°F (6°C) to a freezing cold 28.4°F (-2°C). In December, in Rock Falls, the average low-temperature is a still subzero cold 18°F (-7.8°C).Humidity
In Rock Falls, Iowa, the average relative humidity in December is 85%.Rainfall
In Rock Falls, during December, the rain falls for 5.5 days and regularly aggregates up to 1.34" (34mm) of precipitation. Throughout the year, in Rock Falls, Iowa, there are 129.5 rainfall days, and 25.98" (660mm) of precipitation is accumulated.Snowfall
Months with snowfall in Rock Falls are January through May, October through December. In Rock Falls, Iowa, during December, snow falls for 11.7 days and regularly aggregates up to 3.35" (85mm) of snow. Throughout the year, there are 50.1 snowfall days, and 21.69" (551mm) of snow is accumulated.Daylight
With an average of 9h and 0min of daylight, December has the shortest days of the year.On the first day of December in Rock Falls, sunrise is at 7:25 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:44 am and sunset at 4:47 pm CST.
Sunshine
In December, the average sunshine in Rock Falls is 4.2h.UV index
The months with the lowest UV index in Rock Falls, Iowa, are January and December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: In December, the UV index of 1 transforms into the following advice:
Long-term sun exposure is typically not a concern for most. However, those with sensitive skin, infants, and children must always have protection. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. Attention! Nearly twice the Sun's UV radiation can be reflected by snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Rock Falls, IA
- Average high temperature in December: 28.4°F
The warmest month (with the highest average high temperature) is July (79.3°F).
The month with the lowest average high temperature is January (22.5°F).
- Average low temperature in December: 18°F
The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (10°F).
Average pressure in December
Rock Falls, IA
- Average pressure in December: 30.11"Hg
The months with the highest atmospheric pressure are January and February (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in December
Rock Falls, IA
- Average wind speed in December: 10.1mph
The windiest months (with the highest average wind speed) are January and April (10.7mph).
The calmest month (with the lowest average wind speed) is July (7.2mph).
Average humidity in December
Rock Falls, IA
- Average humidity in December: 85%
The month with the highest relative humidity is January (89%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Rock Falls, IA
- Average rainfall in December: 1.34"
The wettest month (with the highest rainfall) is June (3.98").
The driest month (with the least rainfall) is January (0.94").
Average rainfall days in December
Rock Falls, IA
- Average rainfall days in December: 5.5 days
The month with the highest number of rainy days is June (17.8 days).
The month with the least rainy days is February (3 days).
Average snowfall in December
Rock Falls, IA
- Average snowfall in December: 3.35"
The month with the highest snowfall is February (5.94").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Rock Falls, IA
- Average snowfall days in December: 11.7 days
The month with the highest number of snowfall days is January (12.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Rock Falls, IA
- Average daylight in December: 9h and 0min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in December: 4h and 12min
The months with the most sunshine are July and August (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in December
Rock Falls, IA
- Average sunshine days in December: 16.4 days
The month with the most sunshine days is November (17.7 days).
The month with the least sunshine days is June (10.5 days).
Average UV index in December
Rock Falls, IA
- Average UV index in December: 1
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Rock Falls, IA
- Average cloud cover in December: 58
The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in December
Rock Falls, IA
- Average visibility in December: 6mi
The months with the highest visibility are February, March, April, May, June, August, September, October, November and December (6mi).
The months with the lowest visibility are January and July (5mi).
