December weather forecast
Green Valley, IL

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Weather in December

The first month of the winter, December, is still a cold month in Green Valley, Illinois, with an average temperature ranging between min 26.4°F (-3.1°C) and max 36.9°F (2.7°C).

Temperature

Green Valley, Illinois, experiences a temperature shift at the start of December, with average high-temperatures adjusting from a frosty 48.9°F (9.4°C) in November to a wintry 36.9°F (2.7°C). Green Valley records an average nighttime low of 26.4°F (-3.1°C) in December.

Humidity

The average relative humidity in December is 79%.

Rainfall

In Green Valley, Illinois, in December, it is raining for 6.6 days, with typically 1.06" (27mm) of accumulated precipitation. Throughout the year, there are 131.4 rainfall days, and 20.08" (510mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, November and December. In December, it is snowing for 5.4 days. Throughout December, 1.22" (31mm) of snow is accumulated. In Green Valley, during the entire year, snow falls for 25.8 days and aggregates up to 8.66" (220mm) of snow.

Daylight

With an average of 9h and 18min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 7:03 am and sunset at 4:32 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 4:42 pm CST.

Sunshine

In Green Valley, the average sunshine in December is 4.4h.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a low health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 2 in December interprets into the following advice:
Though the majority can handle prolonged sun exposure, it is crucial to always shield babies, children, and those with fair skin. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation. Heed this! Snow reflection can almost augment the UV radiation of the sun by double.
Updated: Aug 28, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in Green Valley in December?

The high-temperature, in December, in Green Valley, records 36.9°F (2.7°C), while the low-temperature is 26.4°F (-3.1°C). In August, the average heat index (a.k.a. 'real feel', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is appraised at 87.8°F (31°C).

What is the average humidity in December?

In December, the average relative humidity is 79%.

How many days does it rain in December?

In December, the rain falls for 6.6 days. Throughout December, 1.06" (27mm) of precipitation is accumulated.

How many days does it snow in December?

In December, it is snowing for 5.4 days. Throughout December, 1.22" (31mm) of snow is 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?

In December, the average day length in Green Valley is 9h and 21min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:03 am and sunset at 4:32 pm. On the last day of the month, in Green Valley, sunrise is at 7:21 am and sunset at 4:42 pm CST.

How many hours of sunshine does Green Valley have in December?

In Green Valley, the average sunshine duration in December is 4.4h.

What are the months with the lowest UV index?

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index.

How high is the UV index in December?

In Green Valley, Illinois, the average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's 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
Green Valley, IL

Average temperature in December - Green Valley, IL
  • Average high temperature in December: 36.9°F

The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (31.5°F).

  • Average low temperature in December: 26.4°F

The month with the highest average low temperature is July (65.3°F).
The coldest month (with the lowest average low temperature) is January (19.8°F).

Average pressure in December
Green Valley, IL

Average pressure in December - Green Valley, IL
  • Average pressure in December: 30.12"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in December
Green Valley, IL

Average wind speed in December - Green Valley, IL
  • Average wind speed in December: 9.8mph

The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).

Average humidity in December
Green Valley, IL

Average humidity in December - Green Valley, IL
  • Average humidity in December: 79%

The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (71%).

Average rainfall in December
Green Valley, IL

Average rainfall in December - Green Valley, IL
  • Average rainfall in December: 1.06"

The wettest month (with the highest rainfall) is May (2.83").
The driest month (with the least rainfall) is February (1.02").

Average rainfall days in December
Green Valley, IL

Average rainfall days in December - Green Valley, IL
  • Average rainfall days in December: 6.6 days

The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is February (5.1 days).

Average snowfall in December
Green Valley, IL

Average snowfall in December - Green Valley, IL
  • Average snowfall in December: 1.22"

The month with the highest snowfall is January (2.87").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in December
Green Valley, IL

Average snowfall days in December - Green Valley, IL
  • Average snowfall days in December: 5.4 days

The month with the highest number of snowfall days is January (8.4 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Green Valley, IL

Average daylight in December / Average sunshine in December - Green Valley, IL
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 4h and 2min

The month with the most sunshine is June (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).

Average sunshine days in December
Green Valley, IL

Average sunshine days in December - Green Valley, IL
  • Average sunshine days in December: 19.7 days

The month with the most sunshine days is November (20 days).
The month with the least sunshine days is May (11.8 days).

Average UV index in December
Green Valley, IL

Average UV index in December - Green Valley, IL
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in December
Green Valley, IL

Average cloud cover in December - Green Valley, IL
  • Average cloud cover in December: 53

The month with the most cloud cover is January (Cloud cover 57).
The month with the least cloud cover is September (Cloud cover 30).

Average visibility in December
Green Valley, IL

Average visibility in December - Green Valley, IL
  • Average visibility in December: 6mi

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

Green Valley, Illinois, USA

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