December weather forecast
Cromwell, IA

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Weather in December

December, the first month of the winter in Cromwell, is also an icy month, with an average temperature fluctuating between 22.3°F (-5.4°C) and 34.3°F (1.3°C).

Temperature

December's arrival correlates with a reduction in the average high-temperature, down from a chilly 47.3°F (8.5°C) in November to a wintry 34.3°F (1.3°C). Throughout December in Cromwell, a steady low-temperature average of 22.3°F (-5.4°C) is noted.

Humidity

In Cromwell, the average relative humidity in December is 79%.

Rainfall

In December, the rain falls for 5 days. Throughout December, 0.79" (20mm) of precipitation is accumulated. Throughout the year, there are 127.7 rainfall days, and 23.39" (594mm) of precipitation is accumulated.

Snowfall

January through May, October through December are months with snowfall. In Cromwell, during December, snow falls for 6.5 days and regularly aggregates up to 1.69" (43mm) of snow. In Cromwell, during the entire year, snow falls for 32.6 days and aggregates up to 12.01" (305mm) of snow.

Daylight

December has the shortest days of the year, with an average of 9h and 18min of daylight.
On the first day of December, sunrise is at 7:24 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:42 am and sunset at 4:59 pm CST.

Sunshine

The average sunshine in December in Cromwell is 4.8h.

UV index

The average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unsafe exposure to UV radiation for the ordinary person.
Note: A daily maximum UV index of 2 in December translates into the following instructions:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat. Pay attention! The reflection of snow can enhance the Sun's UV radiation almost double.
Updated: Jun 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December?

In December, the average high-temperature and low-temperature are 34.3°F (1.3°C) and 22.3°F (-5.4°C) respectively. In August, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, is estimated at 86°F (30°C).

What is the average humidity in December?

The average relative humidity in December is 79%.

How much does it rain in December?

In Cromwell, during December, the rain falls for 5 days and regularly aggregates up to 0.79" (20mm) of precipitation.

How many days does it snow in December?

In Cromwell, Iowa, during December, snow falls for 6.5 days and regularly aggregates up to 1.69" (43mm) of snow.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 18min of daylight.

How many hours of daylight does Cromwell have in December?

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

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:24 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:42 am and sunset at 4:59 pm CST.

How long on average sun shines in December?

In December, the average sunshine duration is 4.8h.

What is the UV index reading in December?

In December, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes a minimal hazard to health 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
Cromwell, IA

Average temperature in December - Cromwell, IA
  • Average high temperature in December: 34.3°F

The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is January (29.1°F).

  • Average low temperature in December: 22.3°F

The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (15.8°F).

Average pressure in December
Cromwell, IA

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

Average wind speed in December
Cromwell, IA

Average wind speed in December - Cromwell, IA
  • Average wind speed in December: 10.3mph

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

Average humidity in December
Cromwell, IA

Average humidity in December - Cromwell, IA
  • Average humidity in December: 79%

The months with the highest relative humidity are January and June (82%).
The month with the lowest relative humidity is October (71%).

Average rainfall in December
Cromwell, IA

Average rainfall in December - Cromwell, IA
  • Average rainfall in December: 0.79"

The wettest month (with the highest rainfall) is June (4.17").
The driest month (with the least rainfall) is January (0.75").

Average rainfall days in December
Cromwell, IA

Average rainfall days in December - Cromwell, IA
  • Average rainfall days in December: 5 days

The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (3.7 days).

Average snowfall in December
Cromwell, IA

Average snowfall in December - Cromwell, IA
  • Average snowfall in December: 1.69"

The month with the highest snowfall is January (3.15").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Cromwell, IA

Average snowfall days in December - Cromwell, IA
  • Average snowfall days in December: 6.5 days

The month with the highest number of snowfall days is January (8.7 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Cromwell, 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 5min

The month with the most sunshine is July (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days in December
Cromwell, IA

Average sunshine days in December - Cromwell, IA
  • Average sunshine days in December: 19.4 days

The month with the most sunshine days is November (20.2 days).
The month with the least sunshine days is May (10.7 days).

Average UV index in December
Cromwell, IA

Average UV index in December - Cromwell, 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
Cromwell, IA

Average cloud cover in December - Cromwell, IA
  • Average cloud cover in December: 48

The month with the most cloud cover is January (Cloud cover 53).
The months with the least cloud cover are July and September (Cloud cover 30).

Average visibility in December
Cromwell, IA

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

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

Cromwell, Iowa, USA

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