December weather forecast
Decorah, IA

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Weather in December

December rings in the winter season in Decorah, reverting back to the cold weather conditions experienced at the start of the year. Average snowfall increases to 4.57" (116mm), the second-highest for the year, resulting in a white Christmas for the city. Residents bundle up as the temperatures drop and daylight hours are minimized. Despite the cold spell, the allure of a winter wonderland and holiday festivities keep the spirit of Decorah alive. The cascade of snowflakes graces the city, laying a clean white blanket just in time for welcoming the new year.

Temperature

Decorah in December undergoes a mild reduction in the average high-temperature, shifting from November's wintry 41.9°F (5.5°C) to a freezing cold 28.4°F (-2°C). In Decorah, the average temperature during the nights of December drops to 18.3°F (-7.6°C).

Humidity

In Decorah, Iowa, the average relative humidity in December is 86%.

Rainfall

In December, in Decorah, the rain falls for 6.4 days. Throughout December, 1.65" (42mm) of precipitation is accumulated. In Decorah, during the entire year, the rain falls for 149 days and collects up to 30.59" (777mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall in Decorah. In Decorah, Iowa, in December, during 13.1 snowfall days, 4.57" (116mm) of snow is typically accumulated. In Decorah, Iowa, during the entire year, snow falls for 60.9 days and aggregates up to 24.37" (619mm) of snow.

Daylight

The month with the shortest days is December, with an average of 9h and 0min of daylight.
On the first day of the month, sunrise is at 7:20 am and sunset at 4:32 pm. On the last day of December, sunrise is at 7:39 am and sunset at 4:41 pm CST.

Sunshine

In Decorah, the average sunshine in December is 3.9h.

UV index

January, February, November and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV radiation for the ordinary person.
Note: A maximum high UV index of 1 in December translates into the following recommendations:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
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Frequently asked questions

How cold is December in Decorah?

The average high-temperature and low-temperature in Decorah, Iowa, during December are 28.4°F (-2°C) and 18.3°F (-7.6°C) respectively.

What is the average humidity in December in Decorah?

In December, the average relative humidity is 86%.

How many days does it rain in December in Decorah?

In Decorah, Iowa, in December, it is raining for 6.4 days, with typically 1.65" (42mm) of accumulated precipitation.

How many days does it snow in December in Decorah?

In Decorah, Iowa, in December, during 13.1 snowfall days, 4.57" (116mm) of snow is typically accumulated.

What is the month with the shortest days in Decorah?

The month with the shortest days in Decorah is December, with an average of 9h and 0min of daylight.

How many hours of daylight does Decorah have in December?

In December, the average day length in Decorah, Iowa, is 9h and 2min.

What time are sunrise and sunset in December in Decorah?

On the first day of December in Decorah, sunrise is at 7:20 am and sunset at 4:32 pm. On the last day of the month, sunrise is at 7:39 am and sunset at 4:41 pm CST.

How many hours of sunshine does Decorah have in December?

In Decorah, Iowa, the average sunshine duration in December is 3.9h.

When is the lowest UV index in Decorah?

January, February, November and December, with an average maximum UV index of 1, are months with the lowest UV index in Decorah, Iowa.

How high is the UV index in December in Decorah?

In Decorah, the average daily maximum UV index in December is 1. A UV Index estimate of 2, and below, represents a minimal health vulnerability 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
Decorah, IA

Average temperature in December - Decorah, IA
  • Average high temperature in December: 28.4°F

The warmest month (with the highest average high temperature) is July (78.4°F).
The month with the lowest average high temperature is January (22.3°F).

  • Average low temperature in December: 18.3°F

The month with the highest average low temperature is July (61.9°F).
The coldest month (with the lowest average low temperature) is January (9.7°F).

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Average pressure in December
Decorah, IA

Average pressure in December - Decorah, IA
  • Average pressure in December: 30.1"Hg

The months with the highest atmospheric pressure are January and February (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).

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Average wind speed in December
Decorah, IA

Average wind speed in December - Decorah, IA
  • Average wind speed in December: 9.7mph

The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (7mph).

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Average humidity in December
Decorah, IA

Average humidity in December - Decorah, IA
  • Average humidity in December: 86%

The months with the highest relative humidity are January and February (89%).
The month with the lowest relative humidity is October (76%).

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Average rainfall in December
Decorah, IA

Average rainfall in December - Decorah, IA
  • Average rainfall in December: 1.65"

The wettest month (with the highest rainfall) is June (5.04").
The driest month (with the least rainfall) is January (1.1").

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Average rainfall days in December
Decorah, IA

Average rainfall days in December - Decorah, IA
  • Average rainfall days in December: 6.4 days

The months with the highest number of rainy days are May and June (20.3 days).
The month with the least rainy days is February (4.4 days).

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Average snowfall in December
Decorah, IA

Average snowfall in December - Decorah, IA
  • Average snowfall in December: 4.57"

The month with the highest snowfall is February (5.98").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in December
Decorah, IA

Average snowfall days in December - Decorah, IA
  • Average snowfall days in December: 13.1 days

The month with the highest number of snowfall days is January (14.3 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
Decorah, IA

Average daylight in December / Average sunshine in December - Decorah, 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: 3h and 5min

The month with the most sunshine is August (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).

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Average sunshine days in December
Decorah, IA

Average sunshine days in December - Decorah, IA
  • Average sunshine days in December: 14.5 days

The month with the most sunshine days is November (16.2 days).
The month with the least sunshine days is June (7.1 days).

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Average UV index in December
Decorah, IA

Average UV index in December - Decorah, IA
  • Average UV index in December: 1

The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).

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Average cloud cover in December
Decorah, IA

Average cloud cover in December - Decorah, IA
  • Average cloud cover in December: 60

The month with the most cloud cover is January (Cloud cover 64).
The month with the least cloud cover is August (Cloud cover 32).

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Average visibility in December
Decorah, IA

Average visibility in December - Decorah, IA
  • Average visibility in December: 5mi

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

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Decorah, Iowa, USA

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