December weather forecastDerby, IA
December
Weather in December
December, the first month of the winter in Derby, is still a cold month, with an average temperature varying between 34.9°F (1.6°C) and 23.2°F (-4.9°C).Temperature
Derby's December weather features a mild decline in high-temperatures, reducing from a chilly 48°F (8.9°C) in November to a wintry 34.9°F (1.6°C). In the month of December, the average low-temperature usually rests at a subzero cold 23.2°F (-4.9°C).Humidity
In December, the average relative humidity in Derby is 79%.Rainfall
In Derby, in December, during 6.1 rainfall days, 1.06" (27mm) of precipitation is typically accumulated. In Derby, during the entire year, the rain falls for 131.1 days and collects up to 25.71" (653mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. In Derby, in December, during 6.4 snowfall days, 1.54" (39mm) of snow is typically accumulated. Throughout the year, in Derby, there are 33.4 snowfall days, and 13.54" (344mm) of snow is accumulated.Daylight
The month with the shortest days in Derby is December, with an average of 9h and 18min of daylight.On the first day of the month, sunrise is at 7:19 am and sunset at 4:46 pm. On the last day of December, in Derby, sunrise is at 7:38 am and sunset at 4:55 pm CST.
Sunshine
In December, the average sunshine is 4.6h.UV index
The average daily maximum UV index in December in Derby, Iowa, is 2. A UV Index of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.Note: In December, a daily UV index of 2 turns into the following recommendations:
Prolonged sun exposure generally does not trouble most people. However, it is vital to ensure protection for babies, children, and individuals with sensitive skin. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key. Be aware! The reflective nature of snow can magnify the Sun's UV radiation almost twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Derby, IA
- Average high temperature in December: 34.9°F
The warmest month (with the highest average high temperature) is July (83.1°F).
The month with the lowest average high temperature is January (29.3°F).
- Average low temperature in December: 23.2°F
The month with the highest average low temperature is July (65.7°F).
The coldest month (with the lowest average low temperature) is January (16°F).
Average pressure in December
Derby, IA
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in December
Derby, IA
- Average wind speed in December: 10.3mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (7.1mph).
Average humidity in December
Derby, IA
- Average humidity in December: 79%
The month with the highest relative humidity is June (83%).
The month with the lowest relative humidity is October (72%).
Average rainfall in December
Derby, IA
- Average rainfall in December: 1.06"
The wettest month (with the highest rainfall) is June (3.74").
The driest month (with the least rainfall) is January (0.94").
Average rainfall days in December
Derby, IA
- Average rainfall days in December: 6.1 days
The month with the highest number of rainy days is May (16.7 days).
The month with the least rainy days is January (4.7 days).
Average snowfall in December
Derby, IA
- Average snowfall in December: 1.54"
The month with the highest snowfall is February (4.13").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Derby, IA
- Average snowfall days in December: 6.4 days
The month with the highest number of snowfall days is January (10.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Derby, IA
- 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 36min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in December
Derby, IA
- Average sunshine days in December: 19.1 days
The month with the most sunshine days is November (19.3 days).
The month with the least sunshine days is June (10.7 days).
Average UV index in December
Derby, IA
- Average UV index in December: 2
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in December
Derby, IA
- Average cloud cover in December: 50
The month with the most cloud cover is January (Cloud cover 54).
The months with the least cloud cover are July and August (Cloud cover 30).
Average visibility in December
Derby, IA
- Average visibility in December: 6mi
The months with the highest visibility are February, March, April, May, June, July, September, October, November and December (6mi).
The months with the lowest visibility are January and August (5mi).
