December weather forecast
Troy, IL

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Weather in December

The first month of the winter, December, is also an icy month in Troy, Illinois, with an average temperature fluctuating between 30°F (-1.1°C) and 41.9°F (5.5°C).

Temperature

December brings a decrease in the average high-temperature, shifting from a cool 52.9°F (11.6°C) in November to a wintry 41.9°F (5.5°C). Throughout December, the temperature falls to an average low of 30°F (-1.1°C).

Humidity

In December, the average relative humidity is 77%.

Rainfall

In Troy, in December, it is raining for 8.4 days, with typically 2.2" (56mm) of accumulated precipitation. In Troy, Illinois, during the entire year, the rain falls for 149.9 days and collects up to 33.94" (862mm) of precipitation.

Snowfall

January through March, September, November and December are months with snowfall. In Troy, in December, during 3.8 snowfall days, 1.73" (44mm) of snow is typically accumulated. In Troy, during the entire year, snow falls for 20.7 days and aggregates up to 7.13" (181mm) of snow.

Daylight

December has the shortest days of the year, with an average of 9h and 30min of daylight.
On the first day of December, sunrise is at 6:59 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:48 pm CST.

Sunshine

In Troy, the average sunshine in December is 4.8h.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The daily high UV index of 2 during December translates into the following recommendations:
While many people can endure lengthy sun exposure, it remains imperative to safeguard babies, children, and fair-skinned individuals. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Guard yourself! Snow reflection can almost double the UV radiation from the Sun.
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Frequently asked questions

Is December cold in Troy?

The high-temperature, in December, in Troy, records 41.9°F (5.5°C), while the low-temperature is 30°F (-1.1°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which takes the relative humidity and factors it into the air temperature reading, in August is appraised at 93.2°F (34°C).

What is the average humidity in December in Troy?

The average relative humidity in December in Troy is 77%.

How many days does it rain in December in Troy?

In Troy, in December, it is raining for 8.4 days, with typically 2.2" (56mm) of accumulated precipitation.

How much does it snow in Troy in December?

In Troy, Illinois, in December, during 3.8 snowfall days, 1.73" (44mm) of snow is typically accumulated.

What is the month with the shortest days in Troy?

With an average of 9h and 30min of daylight, December has the shortest days of the year in Troy.

How many hours of daylight does Troy have in December?

In December, the average day length in Troy is 9h and 31min.

What time are sunrise and sunset in December in Troy?

On the first day of December in Troy, Illinois, sunrise is at 6:59 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:48 pm CST.

How long on average sun shines in December in Troy?

In December, the average sunshine duration is 4.8h.

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

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

What is the UV index intensity in December in Troy?

In Troy, 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
Troy, IL

Average temperature in December - Troy, IL
  • Average high temperature in December: 41.9°F

The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (37.4°F).

  • Average low temperature in December: 30°F

The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).

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Average pressure in December
Troy, IL

Average pressure in December - Troy, IL
  • 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 (29.92"Hg).

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Average wind speed in December
Troy, IL

Average wind speed in December - Troy, IL
  • Average wind speed in December: 8.8mph

The windiest month (with the highest average wind speed) is January (9.5mph).
The calmest month (with the lowest average wind speed) is July (5.6mph).

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Average humidity in December
Troy, IL

Average humidity in December - Troy, IL
  • Average humidity in December: 77%

The months with the highest relative humidity are May, July and August (79%).
The month with the lowest relative humidity is October (71%).

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Average rainfall in December
Troy, IL

Average rainfall in December - Troy, IL
  • Average rainfall in December: 2.2"

The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is February (1.77").

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Average rainfall days in December
Troy, IL

Average rainfall days in December - Troy, IL
  • Average rainfall days in December: 8.4 days

The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is January (7.8 days).

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Average snowfall in December
Troy, IL

Average snowfall in December - Troy, IL
  • Average snowfall in December: 1.73"

The month with the highest snowfall is January (2.13").
The months with the least snowfall are April, May, June, July, August and October (0").

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Average snowfall days in December
Troy, IL

Average snowfall days in December - Troy, IL
  • Average snowfall days in December: 3.8 days

The month with the highest number of snowfall days is January (7 days).
The months with the least snowfall days are May, June, July and August (0 days).

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

Average daylight in December / Average sunshine in December - Troy, IL
  • Average daylight in December: 9h and 3min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in December: 4h and 5min

The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).

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Average sunshine days in December
Troy, IL

Average sunshine days in December - Troy, IL
  • Average sunshine days in December: 18.6 days

The month with the most sunshine days is December (18.6 days).
The month with the least sunshine days is May (11.6 days).

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Average UV index in December
Troy, IL

Average UV index in December - Troy, IL
  • Average UV index in December: 2

The months with the highest UV index are May, 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
Troy, IL

Average cloud cover in December - Troy, IL
  • Average cloud cover in December: 49

The month with the most cloud cover is January (Cloud cover 51).
The months with the least cloud cover are June and August (Cloud cover 28).

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Average visibility in December
Troy, IL

Average visibility in December - Troy, IL
  • 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).

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Troy, Illinois, USA

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