December weather forecastAlton, IN

December

Weather in December

The first month of the winter, December, is still a chilly month in Alton, Indiana, with an average temperature ranging between min 31.8°F (-0.1°C) and max 43.9°F (6.6°C).

Temperature

Setting in of December comes with a decrease in the average high-temperature, moving from a fresh 52.9°F (11.6°C) in November to a chilly 43.9°F (6.6°C). Alton sees an average low-temperature of 31.8°F (-0.1°C) during December.

Humidity

February and December, with an average relative humidity of 80%, are the most humid months.

Rainfall

In Alton, in December, during 11.3 rainfall days, 2.2" (56mm) of precipitation is typically accumulated. Throughout the year, there are 160 rainfall days, and 29.45" (748mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, September through December. In Alton, in December, snow falls for 5.5 days, with typically accumulated 1.14" (29mm) of snow. In Alton, during the entire year, snow falls for 26.8 days and aggregates up to 7.91" (201mm) of snow.

Daylight

With an average of 9h and 36min of daylight, December has the shortest days of the year in Alton.
On the first day of the month, sunrise is at 7:43 am and sunset at 5:26 pm. On the last day of December, sunrise is at 8:01 am and sunset at 5:36 pm EST.

Sunshine

With an average of 4.4h of sunshine, December has the least sunshine of the year.

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 reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for the ordinary person.
Note: In December, the maximum UV index of 2 translates into these guidelines:
Though extended exposure to the sun typically does not concern most people, it is crucial to always shield children, infants, and those with sensitive skin. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Heads up! The UV radiation from the Sun can almost be doubled by snow reflection.
Updated: Aug 25, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

An average high-temperature, in December, in Alton, is 43.9°F (6.6°C) and the average low-temperature is 31.8°F (-0.1°C). In August, the average heat index (a.k.a. 'real feel', 'felt air temperature'), which combines relative humidity and air temperature, is estimated at 96.8°F (36°C).

February and December, with an average relative humidity of 80%, are most humid months.

In December, the average relative humidity is 80%.

In Alton, in December, it is raining for 11.3 days, with typically 2.2" (56mm) of accumulated precipitation.

In Alton, in December, during 5.5 snowfall days, 1.14" (29mm) of snow is typically accumulated.

With an average of 9h and 36min of daylight, December has the shortest days of the year.

In December, the average day length in Alton is 9h and 34min.

On the first day of December, sunrise is at 7:43 am and sunset at 5:26 pm. On the last day of the month, sunrise is at 8:01 am and sunset at 5:36 pm EST.

With an average of 4.4h of sunshine, December has the least sunshine of the year.

In December, the average sunshine duration is 4.4h.

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

In December, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes a low health risk from unsafe exposure to Sun's UV rays.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Alton, IN

  • Average high temperature in December: 43.9°F

The warmest month (with the highest average high temperature) is July (86.5°F).
The month with the lowest average high temperature is January (38.8°F).

  • Average low temperature in December: 31.8°F

The month with the highest average low temperature is July (67.1°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).

Average pressure in December
Alton, IN

  • 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 (29.95"Hg).

Average wind speed in December
Alton, IN

  • Average wind speed in December: 7.1mph

The windiest months (with the highest average wind speed) are January and February (7.7mph).
The calmest months (with the lowest average wind speed) are July and August (4.8mph).

Average humidity in December
Alton, IN

  • Average humidity in December: 80%

The months with the highest relative humidity are February and December (80%).
The month with the lowest relative humidity is October (74%).

Average rainfall in December
Alton, IN

  • Average rainfall in December: 2.2"

The wettest month (with the highest rainfall) is April (3.31").
The driest month (with the least rainfall) is September (1.61").

Average rainfall days in December
Alton, IN

  • Average rainfall days in December: 11.3 days

The month with the highest number of rainy days is May (18.7 days).
The month with the least rainy days is November (9.8 days).

Average snowfall in December
Alton, IN

  • Average snowfall in December: 1.14"

The month with the highest snowfall is January (2.24").
The months with the least snowfall are May, June, July and August (0").

Average snowfall days in December
Alton, IN

  • Average snowfall days in December: 5.5 days

The month with the highest number of snowfall days is January (7.6 days).
The months with the least snowfall days are May, June, July and August (0 days).

Average daylight in December /
Average sunshine in December
Alton, IN

  • Average daylight in December: 9h and 36min

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 36min).

  • Average sunshine in December: 4h and 24min

The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is December (Average sunshine: 4h and 24min).

Average sunshine days in December
Alton, IN

  • Average sunshine days in December: 15.2 days

The month with the most sunshine days is October (19.1 days).
The month with the least sunshine days is May (11.1 days).

Average UV index in December
Alton, IN

  • 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).

Average cloud cover in December
Alton, IN

  • Average cloud cover in December: 55

The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 29).

Average visibility in December
Alton, IN

  • Average visibility in December: 5mi

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