December weather forecast
Grand River, IA

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Weather in December

The first month of the winter, December, is also a wintry month in Grand River, Iowa, with temperature in the range of an average high of 35.6°F (2°C) and an average low of 23.4°F (-4.8°C).

Temperature

The arrival of December corresponds with a shift in temperature, down from a frosty 48.6°F (9.2°C) in November to a cold 35.6°F (2°C). During December, Grand River experiences an average low-temperature of 23.4°F (-4.8°C) at night.

Humidity

In December, the average relative humidity is 79%.

Rainfall

The months with the least rainfall are January and December Rain falls for 5.7 days and accumulates 0.67" (17mm) of rain.

Snowfall

Months with snowfall are January through May, October through December. In Grand River, during December, snow falls for 5.9 days and regularly aggregates up to 1.14" (29mm) of snow. Throughout the year, there are 30.2 snowfall days, and 10.16" (258mm) of snow is accumulated.

Daylight

December has the shortest days of the year, with an average of 9h and 18min of daylight.
On the first day of the month, sunrise is at 7:21 am and sunset at 4:48 pm. On the last day of December, sunrise is at 7:40 am and sunset at 4:58 pm CST.

Sunshine

In Grand River, the average sunshine in December is 4.9h.

UV index

In December, the average daily maximum UV index is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV radiation for ordinary individuals.
Note: An average maximum UV index of 2 in December leads to these recommendations:
Apart from children, who require continuous protection, most can endure sun exposure for up to an hour without experiencing burns. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades. Be cautious! The UV radiation from the Sun can be magnified almost twofold by snow reflection.
Updated: Aug 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in December?

The high-temperature, in December, in Grand River, is 35.6°F (2°C), while the low-temperature averages to 23.4°F (-4.8°C). The average heat index (a.k.a. 'real feel', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, in August is computed to be 87.8°F (31°C).

What is the average humidity in December?

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

What is the driest month?

January and December are months with the least rain when the rain falls for 5.7 days and typically aggregates up to 0.67" (17mm) of rain.

How many days does it rain in December?

In December, in Grand River, the rain falls for 5.7 days. Throughout December, 0.67" (17mm) of precipitation is accumulated.

How many days does it snow in December?

In Grand River, in December, during 5.9 snowfall days, 1.14" (29mm) of snow is typically accumulated.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 18min of daylight.

What is the average length of the day in December?

The average day length in December is 9h and 18min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 7:21 am and sunset at 4:48 pm. On the last day of the month, sunrise is at 7:40 am and sunset at 4:58 pm CST.

How long on average sun shines in December?

In Grand River, the average sunshine duration in December is 4.9h.

What is the UV index intensity in December?

In Grand River, the average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to UV radiation.
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
Grand River, IA

Average temperature in December - Grand River, IA
  • Average high temperature in December: 35.6°F

The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (30.6°F).

  • Average low temperature in December: 23.4°F

The month with the highest average low temperature is July (66°F).
The coldest month (with the lowest average low temperature) is January (16.9°F).

Average pressure in December
Grand River, IA

Average pressure in December - Grand River, 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
Grand River, IA

Average wind speed in December - Grand River, IA
  • Average wind speed in December: 9.9mph

The windiest months (with the highest average wind speed) are January, February and March (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.9mph).

Average humidity in December
Grand River, IA

Average humidity in December - Grand River, 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
Grand River, IA

Average rainfall in December - Grand River, IA
  • Average rainfall in December: 0.67"

The wettest month (with the highest rainfall) is June (3.43").
The driest months (with the least rainfall) are January and December (0.67").

Average rainfall days in December
Grand River, IA

Average rainfall days in December - Grand River, IA
  • Average rainfall days in December: 5.7 days

The month with the highest number of rainy days is June (17.3 days).
The month with the least rainy days is January (4.8 days).

Average snowfall in December
Grand River, IA

Average snowfall in December - Grand River, IA
  • Average snowfall in December: 1.14"

The month with the highest snowfall is January (2.72").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Grand River, IA

Average snowfall days in December - Grand River, IA
  • Average snowfall days in December: 5.9 days

The month with the highest number of snowfall days is January (8.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Grand River, IA

Average daylight in December / Average sunshine in December - Grand River, 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 24min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days in December
Grand River, IA

Average sunshine days in December - Grand River, IA
  • Average sunshine days in December: 20.3 days

The month with the most sunshine days is December (20.3 days).
The month with the least sunshine days is June (8.9 days).

Average UV index in December
Grand River, IA

Average UV index in December - Grand River, 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
Grand River, IA

Average cloud cover in December - Grand River, IA
  • Average cloud cover in December: 47

The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is July (Cloud cover 28).

Average visibility in December
Grand River, IA

Average visibility in December - Grand River, 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).

Grand River, Iowa, USA

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