December weather forecast
Bethalto, IL

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Weather in December

The first month of the winter, December, is also a wintry month in Bethalto, Illinois, with an average temperature ranging between min 29.8°F (-1.2°C) and max 41.4°F (5.2°C).

Temperature

The shift from November to December involves a decrease in the average high-temperature, dropping from a cool 52.2°F (11.2°C) to a cold 41.4°F (5.2°C). An average low-temperature of 29.8°F (-1.2°C) is recorded in the month of December.

Humidity

In Bethalto, the average relative humidity in December is 77%.

Rainfall

In Bethalto, in December, it is raining for 6.7 days, with typically 1.38" (35mm) of accumulated precipitation. Throughout the year, in Bethalto, there are 138 rainfall days, and 23.9" (607mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, November and December. In Bethalto, during December, snow falls for 3.8 days and regularly aggregates up to 0.91" (23mm) of snow. Throughout the year, there are 18.6 snowfall days, and 4.53" (115mm) of snow is accumulated.

Daylight

December has the shortest days of the year in Bethalto, with an average of 9h and 30min of daylight.
On the first day of the month, sunrise is at 7:00 am and sunset at 4:38 pm. On the last day of December, in Bethalto, sunrise is at 7:18 am and sunset at 4:48 pm CST.

Sunshine

In Bethalto, 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 low threat to health from exposure to the Sun's UV rays for average individuals.
Note: The maximum daily UV index, 2 in December, converts into the following recommendations:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
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Frequently asked questions

How cold is it in Bethalto in December?

In December, in Bethalto, the average high-temperature is 41.4°F (5.2°C), and the average low-temperature is 29.8°F (-1.2°C). In August, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which combines air temperature and relative humidity, is estimated at 93.2°F (34°C).

What is the average humidity in December in Bethalto?

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

How many days does it rain in December in Bethalto?

In Bethalto, during December, the rain falls for 6.7 days and regularly aggregates up to 1.38" (35mm) of precipitation.

How many days does it snow in December in Bethalto?

In Bethalto, Illinois, during December, snow falls for 3.8 days and regularly aggregates up to 0.91" (23mm) of snow.

What is the month with the shortest days in Bethalto?

The month with the shortest days is December, with an average of 9h and 30min of daylight.

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

The average day length in December in Bethalto is 9h and 29min.

What time are sunrise and sunset in December in Bethalto?

On the first day of December in Bethalto, sunrise is at 7:00 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 4:48 pm CST.

How many hours of sunshine does Bethalto have in December?

The average sunshine duration in December in Bethalto is 4.8h.

When is the lowest UV index in Bethalto?

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

How high is the UV index in December in Bethalto?

In December, the average daily maximum UV index is 2. A UV Index reading of 2, and below, represents a low health threat 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
Bethalto, IL

Average temperature in December - Bethalto, IL
  • Average high temperature in December: 41.4°F

The warmest month (with the highest average high temperature) is July (85.3°F).
The month with the lowest average high temperature is January (36.1°F).

  • Average low temperature in December: 29.8°F

The month with the highest average low temperature is July (67.6°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).

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Average pressure in December
Bethalto, IL

Average pressure in December - Bethalto, 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
Bethalto, IL

Average wind speed in December - Bethalto, IL
  • Average wind speed in December: 9mph

The windiest months (with the highest average wind speed) are January and February (9.6mph).
The calmest month (with the lowest average wind speed) is July (5.7mph).

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Average humidity in December
Bethalto, IL

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

The month with the highest relative humidity is July (80%).
The month with the lowest relative humidity is October (71%).

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Average rainfall in December
Bethalto, IL

Average rainfall in December - Bethalto, IL
  • Average rainfall in December: 1.38"

The wettest month (with the highest rainfall) is May (3.07").
The driest month (with the least rainfall) is February (1.14").

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Average rainfall days in December
Bethalto, IL

Average rainfall days in December - Bethalto, IL
  • Average rainfall days in December: 6.7 days

The month with the highest number of rainy days is May (16.6 days).
The month with the least rainy days is January (5.6 days).

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Average snowfall in December
Bethalto, IL

Average snowfall in December - Bethalto, IL
  • Average snowfall in December: 0.91"

The month with the highest snowfall is February (1.61").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in December
Bethalto, IL

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

The month with the highest number of snowfall days is January (6 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
Bethalto, IL

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

The month with the longest days is June (Average daylight: 14h and 54min).
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 24min).
The months with the least sunshine are January and February (Average sunshine: 4h and 30min).

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Average sunshine days in December
Bethalto, IL

Average sunshine days in December - Bethalto, IL
  • Average sunshine days in December: 20.4 days

The month with the most sunshine days is December (20.4 days).
The month with the least sunshine days is July (12.3 days).

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Average UV index in December
Bethalto, IL

Average UV index in December - Bethalto, 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
Bethalto, IL

Average cloud cover in December - Bethalto, 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, July and August (Cloud cover 29).

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Average visibility in December
Bethalto, IL

Average visibility in December - Bethalto, 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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Bethalto, Illinois, USA

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