December weather forecast
Derby, IA

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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.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in Derby in December?

December temperatures vary between a high-temperature of 34.9°F (1.6°C) and a low-temperature of 23.2°F (-4.9°C). In August, the average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which takes the relative humidity and factors it into the air temperature reading, is evaluated at 87.8°F (31°C).

What is the average humidity in December in Derby?

The average relative humidity in December in Derby, Iowa, is 79%.

How much does it rain in Derby in December?

In December, in Derby, the rain falls for 6.1 days. Throughout December, 1.06" (27mm) of precipitation is accumulated.

How much does it snow in Derby in December?

In Derby, in December, snow falls for 6.4 days, with typically accumulated 1.54" (39mm) of snow.

What is the month with the shortest days in Derby?

With an average of 9h and 18min of daylight, December has the shortest days of the year in Derby, Iowa.

What is the average length of the day in December in Derby?

In Derby, the average day length in December is 9h and 17min.

When are sunrise and sunset in December in Derby?

On the first day of December in Derby, sunrise is at 7:19 am and sunset at 4:46 pm. On the last day of the month, sunrise is at 7:38 am and sunset at 4:55 pm CST.

How long on average sun shines in December in Derby?

In Derby, Iowa, the average sunshine duration in December is 4.6h.

What is the UV index intensity in December in Derby?

In December, the average daily maximum UV index in Derby is 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Derby, IA

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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 / Average sunshine in December - Derby, IA
  • Average daylight in December: 9h and 2min

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 4min

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 - 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 - 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 - 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 - 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).

Derby, Iowa, USA

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