December weather forecast
Jefferson, IA

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Weather in December

The first month of the winter, December, is also a wintry month in Jefferson, Iowa, with an average temperature ranging between max 32°F (0°C) and min 21°F (-6.1°C).

Temperature

December brings a decrease in the average high-temperature, falling from November's frosty 45.9°F (7.7°C) to a cold 32°F (0°C). Jefferson registers a consistent average low-temperature of 21°F (-6.1°C) during December.

Humidity

In December, the average relative humidity in Jefferson is 80%.

Rainfall

In Jefferson, in December, during 4.8 rainfall days, 1.34" (34mm) of precipitation is typically accumulated. In Jefferson, during the entire year, the rain falls for 125.7 days and collects up to 26.5" (673mm) of precipitation.

Snowfall

Months with snowfall in Jefferson are January through May, October through December. In Jefferson, Iowa, in December, snow falls for 8.3 days, with typically accumulated 2.64" (67mm) of snow. Throughout the year, there are 38.1 snowfall days, and 15.31" (389mm) of snow is accumulated.

Daylight

With an average of 9h and 12min of daylight, December has the shortest days of the year in Jefferson.
On the first day of December, sunrise is at 7:26 am and sunset at 4:46 pm. On the last day of the month, sunrise is at 7:45 am and sunset at 4:56 pm CST.

Sunshine

In December, the average sunshine in Jefferson, Iowa, is 4.7h.

UV index

The months with the lowest UV index in Jefferson, Iowa, are January, February, October through December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a minimal health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: The maximum UV index of 2 during December translates into these guidelines:
Though the majority can handle prolonged sun exposure, it is crucial to always shield babies, children, and those with fair skin. The solar radiation around mid-day is intense; avoid the Sun and stay safe. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection. Be cautious! The UV radiation from the Sun can be magnified almost twofold by snow reflection.
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Frequently asked questions

How cold is it in Jefferson in December?

The high-temperature in Jefferson during December is 32°F (0°C) and the low-temperature is 21°F (-6.1°C). In July, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which combines relative humidity and air temperature, is appraised at 89.6°F (32°C).

What is the average humidity in December in Jefferson?

The average relative humidity in December is 80%.

How much does it rain in Jefferson in December?

In Jefferson, during December, the rain falls for 4.8 days and regularly aggregates up to 1.34" (34mm) of precipitation.

How much does it snow in Jefferson in December?

In Jefferson, during December, snow falls for 8.3 days and regularly aggregates up to 2.64" (67mm) of snow.

What is the month with the shortest days in Jefferson?

December has the shortest days of the year in Jefferson, with an average of 9h and 12min of daylight.

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

In December, the average day length is 9h and 11min.

When is the sunrise / sunset in December in Jefferson?

On the first day of December in Jefferson, sunrise is at 7:26 am and sunset at 4:46 pm. On the last day of the month, sunrise is at 7:45 am and sunset at 4:56 pm CST.

How many hours of sunshine does Jefferson have in December?

The average sunshine duration in December is 4.7h.

What is the month with the lowest UV index in Jefferson?

January, February, October through December, with an average maximum UV index of 2, are months with the lowest UV index in Jefferson.

What is the UV index intensity in December in Jefferson?

The average daily maximum UV index in December in Jefferson is 2. A UV Index reading of 2, and below, represents a low health threat from 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
Jefferson, IA

Average temperature in December - Jefferson, IA
  • Average high temperature in December: 32°F

The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (26.8°F).

  • Average low temperature in December: 21°F

The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).

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Average pressure in December
Jefferson, IA

Average pressure in December - Jefferson, 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 (29.88"Hg).

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Average wind speed in December
Jefferson, IA

Average wind speed in December - Jefferson, IA
  • Average wind speed in December: 10.2mph

The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (7.1mph).

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Average humidity in December
Jefferson, IA

Average humidity in December - Jefferson, IA
  • Average humidity in December: 80%

The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (69%).

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Average rainfall in December
Jefferson, IA

Average rainfall in December - Jefferson, IA
  • Average rainfall in December: 1.34"

The wettest month (with the highest rainfall) is May (4.06").
The driest month (with the least rainfall) is January (0.87").

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Average rainfall days in December
Jefferson, IA

Average rainfall days in December - Jefferson, IA
  • Average rainfall days in December: 4.8 days

The month with the highest number of rainy days is June (17.3 days).
The month with the least rainy days is February (3.4 days).

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Average snowfall in December
Jefferson, IA

Average snowfall in December - Jefferson, IA
  • Average snowfall in December: 2.64"

The month with the highest snowfall is January (4.29").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in December
Jefferson, IA

Average snowfall days in December - Jefferson, IA
  • Average snowfall days in December: 8.3 days

The month with the highest number of snowfall days is January (9.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in December /
Average sunshine in December
Jefferson, IA

Average daylight in December / Average sunshine in December - Jefferson, IA
  • Average daylight in December: 9h and 1min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • 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).

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Average sunshine days in December
Jefferson, IA

Average sunshine days in December - Jefferson, IA
  • Average sunshine days in December: 18.8 days

The month with the most sunshine days is November (19.4 days).
The month with the least sunshine days is June (11.1 days).

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Average UV index in December
Jefferson, IA

Average UV index in December - Jefferson, 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).

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Average cloud cover in December
Jefferson, IA

Average cloud cover in December - Jefferson, IA
  • Average cloud cover in December: 50

The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are July and September (Cloud cover 30).

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Average visibility in December
Jefferson, IA

Average visibility in December - Jefferson, IA
  • Average visibility in December: 6mi

The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).

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Jefferson, Iowa, USA

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