December weather forecast
Williamsville, IL

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Weather in December

December, the first month of the winter in Williamsville, is also an icy month, with an average temperature fluctuating between 28.2°F (-2.1°C) and 38.7°F (3.7°C).

Temperature

In Williamsville, the average high-temperature in December drops from a cool 50°F (10°C) in November to a wintry 38.7°F (3.7°C). Nighttime temperature in Williamsville lowers to an average of 28.2°F (-2.1°C) in December.

Humidity

The average relative humidity in December is 78%.

Rainfall

The month with the least rainfall in Williamsville is December, when the rain falls for 6.6 days and typically collects 0.83" (21mm) of precipitation.

Snowfall

January through April, November and December are months with snowfall in Williamsville. In December, in Williamsville, it is snowing for 4.8 days. Throughout December, 0.59" (15mm) of snow is accumulated. In Williamsville, during the entire year, snow falls for 24.5 days and aggregates up to 5.51" (140mm) of snow.

Daylight

With an average of 9h and 24min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 7:01 am and sunset at 4:33 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 4:43 pm CST.

Sunshine

The average sunshine in December is 4.7h.

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 of 2, and less, symbolizes a minimal health hazard from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The maximum daily UV index, 2 in December, converts into the following recommendations:
Protection from prolonged sun exposure is necessary for babies, children, and individuals with sensitive skin. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Take precaution! The reflection from snow can almost double the UV radiation of the Sun.
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Frequently asked questions

How cold is December in Williamsville?

The average high-temperature, in December, in Williamsville, is 38.7°F (3.7°C), while the average low-temperature is 28.2°F (-2.1°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which factors the actual air temperature with the relative humidity, in August is appraised at 87.8°F (31°C).

What is the average humidity in December in Williamsville?

In Williamsville, the average relative humidity in December is 78%.

What is the driest month in Williamsville?

The month with the least rainfall in Williamsville is December, when the rain falls for 6.6 days and typically collects 0.83" (21mm) of precipitation.

How many days does it rain in December in Williamsville?

In December, in Williamsville, Illinois, the rain falls for 6.6 days. Throughout December, 0.83" (21mm) of precipitation is accumulated.

How much does it snow in Williamsville in December?

In Williamsville, Illinois, in December, snow falls for 4.8 days, with typically accumulated 0.59" (15mm) of snow.

What is the month with the shortest days in Williamsville?

With an average of 9h and 24min of daylight, December has the shortest days of the year in Williamsville, Illinois.

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

The average day length in December is 9h and 23min.

When are sunrise and sunset in December in Williamsville?

In December, on the first day of the month, sunrise is at 7:01 am and sunset at 4:33 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 4:43 pm CST.

How long on average sun shines in December in Williamsville?

The average sunshine duration in December in Williamsville is 4.7h.

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

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

What is the UV index reading in December in Williamsville?

In December, the average daily maximum UV index in Williamsville is 2. A UV Index of 2, and less, symbolizes a low health risk 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
Williamsville, IL

Average temperature in December - Williamsville, IL
  • Average high temperature in December: 38.7°F

The warmest month (with the highest average high temperature) is July (82.8°F).
The month with the lowest average high temperature is January (33.1°F).

  • Average low temperature in December: 28.2°F

The month with the highest average low temperature is July (66°F).
The coldest month (with the lowest average low temperature) is January (20.8°F).

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Average pressure in December
Williamsville, IL

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

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in December
Williamsville, IL

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

The windiest months (with the highest average wind speed) are January and April (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.2mph).

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Average humidity in December
Williamsville, IL

Average humidity in December - Williamsville, IL
  • Average humidity in December: 78%

The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).

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Average rainfall in December
Williamsville, IL

Average rainfall in December - Williamsville, IL
  • Average rainfall in December: 0.83"

The wettest month (with the highest rainfall) is June (2.36").
The driest month (with the least rainfall) is December (0.83").

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Average rainfall days in December
Williamsville, IL

Average rainfall days in December - Williamsville, IL
  • Average rainfall days in December: 6.6 days

The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is February (5.7 days).

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Average snowfall in December
Williamsville, IL

Average snowfall in December - Williamsville, IL
  • Average snowfall in December: 0.59"

The month with the highest snowfall is January (1.81").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in December
Williamsville, IL

Average snowfall days in December - Williamsville, IL
  • Average snowfall days in December: 4.8 days

The month with the highest number of snowfall days is January (8 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

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Average daylight in December /
Average sunshine in December
Williamsville, IL

Average daylight in December / Average sunshine in December - Williamsville, 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 24min).

  • Average sunshine in December: 4h and 4min

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

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Average sunshine days in December
Williamsville, IL

Average sunshine days in December - Williamsville, IL
  • Average sunshine days in December: 20.5 days

The month with the most sunshine days is December (20.5 days).
The month with the least sunshine days is May (11.5 days).

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Average UV index in December
Williamsville, IL

Average UV index in December - Williamsville, 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).

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Average cloud cover in December
Williamsville, IL

Average cloud cover in December - Williamsville, IL
  • Average cloud cover in December: 51

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

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Average visibility in December
Williamsville, IL

Average visibility in December - Williamsville, 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).

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Williamsville, Illinois, USA

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