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
Rock Valley in December showcases a distinct temperature shift, moving from an average high of a frosty 43.7°F (6.5°C) in November to a freezing cold 28°F (-2.2°C). Nighttime temperatures in December average to a still subzero cold 16.7°F (-8.5°C) in Rock Valley, Iowa.Humidity
In Rock Valley, the average relative humidity in December is 84%.Rainfall
In Rock Valley, in December, it is raining for 4.9 days, with typically 1.3" (33mm) of accumulated precipitation. In Rock Valley, during the entire year, the rain falls for 130 days and collects up to 24.09" (612mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In December, it is snowing for 11 days. Throughout December, 3.54" (90mm) of snow is accumulated. Throughout the year, in Rock Valley, there are 49.2 snowfall days, and 19.41" (493mm) of snow is accumulated.Daylight
With an average of 9h and 0min of daylight, December has the shortest days of the year in Rock Valley, Iowa.On the first day of the month, sunrise is at 7:38 am and sunset at 4:50 pm. On the last day of December, sunrise is at 7:57 am and sunset at 4:59 pm CST.
Sunshine
In December, the average sunshine is 4.5h.UV index
The months with the lowest UV index in Rock Valley, Iowa, are January, February, October through December, with an average maximum UV index of 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: In December, the average maximum UV index of 2 translates into the following recommendations:
Although the majority can endure up to an hour in the sun without burns, children always require sun protection. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage. Notice! The UV radiation of the Sun can be intensified nearly twofold due to the reflective quality of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in Rock Valley in December?
What is the average humidity in December in Rock Valley?
How many days does it rain in December in Rock Valley?
How many days does it snow in December in Rock Valley?
What is the month with the shortest days in Rock Valley?
How many hours of daylight does Rock Valley have in December?
When are sunrise and sunset in December in Rock Valley?
How many hours of sunshine does Rock Valley have in December?
What are the months with the lowest UV index in Rock Valley?
What is the UV index intensity in December in Rock Valley?
Average temperature in December
Rock Valley, IA
- Average high temperature in December: 28°F
The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (24.1°F).
- Average low temperature in December: 16.7°F
The month with the highest average low temperature is July (63.5°F).
The coldest month (with the lowest average low temperature) is January (10.8°F).
Average pressure in December
Rock Valley, IA
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).
Average wind speed in December
Rock Valley, IA
- Average wind speed in December: 10mph
The windiest month (with the highest average wind speed) is April (11.2mph).
The calmest month (with the lowest average wind speed) is July (7.8mph).
Average humidity in December
Rock Valley, IA
- Average humidity in December: 84%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (67%).
Average rainfall in December
Rock Valley, IA
- Average rainfall in December: 1.3"
The wettest month (with the highest rainfall) is June (3.78").
The driest month (with the least rainfall) is January (0.75").
Average rainfall days in December
Rock Valley, IA
- Average rainfall days in December: 4.9 days
The month with the highest number of rainy days is June (18.8 days).
The month with the least rainy days is February (3.3 days).
Average snowfall in December
Rock Valley, IA
- Average snowfall in December: 3.54"
The month with the highest snowfall is February (4.49").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Rock Valley, IA
- Average snowfall days in December: 11 days
The month with the highest number of snowfall days is January (11.8 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 Valley, 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 3min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in December
Rock Valley, IA
- Average sunshine days in December: 18 days
The month with the most sunshine days is November (19.7 days).
The month with the least sunshine days is June (8.3 days).
Average UV index in December
Rock Valley, IA
- Average UV index in December: 2
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in December
Rock Valley, IA
- Average cloud cover in December: 52
The month with the most cloud cover is January (Cloud cover 55).
The month with the least cloud cover is July (Cloud cover 27).
Average visibility in December
Rock Valley, IA
- Average visibility in December: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
Rock Valley, Iowa, USA
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