December weather forecast
Petersburg, IL

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Weather in December

The first month of the winter, December, is also an icy month in Petersburg, Illinois, with an average temperature ranging between max 38.5°F (3.6°C) and min 27.5°F (-2.5°C).

Temperature

With December's arrival, Petersburg, Illinois, sees a decrease in average high-temperatures, moving from a fresh 50°F (10°C) in November to a wintry 38.5°F (3.6°C). Throughout the month of December, the nighttime temperature dips to an average of 27.5°F (-2.5°C).

Humidity

The average relative humidity in December in Petersburg is 78%.

Rainfall

The month with the least rainfall in Petersburg, Illinois, is December, when the rain falls for 8.1 days and typically collects 1.5" (38mm) of precipitation.

Snowfall

January through April, October through December are months with snowfall in Petersburg. In Petersburg, in December, snow falls for 4.8 days, with typically accumulated 1.46" (37mm) of snow. In Petersburg, during the entire year, snow falls for 29.2 days and aggregates up to 10.39" (264mm) of snow.

Daylight

The month with the shortest days in Petersburg, Illinois, is December, with an average of 9h and 24min of daylight.
On the first day of the month, sunrise is at 7:02 am and sunset at 4:34 pm. On the last day of December, in Petersburg, sunrise is at 7:21 am and sunset at 4:44 pm CST.

Sunshine

In Petersburg, the average sunshine in December is 4.5h.

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 estimate of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV rays for ordinary individuals.
Note: An average UV index of 2 in December transforms into this advice:
Most individuals face no major issues with lengthy exposure to the sun, but children, infants, and individuals with fair skin always require protection. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage. Heed this! Snow reflection can almost augment the UV radiation of the sun by double.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is December cold in Petersburg?

The high-temperature, in December, in Petersburg, is 38.5°F (3.6°C), while the low-temperature averages to 27.5°F (-2.5°C). In August, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is computed to be 89.6°F (32°C).

What is the average humidity in December in Petersburg?

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

What is the driest month in Petersburg?

December is the month with the least rainfall in Petersburg, Illinois. Rain falls for 8.1 days and accumulates 1.5" (38mm) of precipitation.

How many days does it rain in December in Petersburg?

In Petersburg, Illinois, in December, during 8.1 rainfall days, 1.5" (38mm) of precipitation is typically accumulated.

How much does it snow in Petersburg in December?

In Petersburg, in December, snow falls for 4.8 days, with typically accumulated 1.46" (37mm) of snow.

What is the month with the shortest days in Petersburg?

The month with the shortest days in Petersburg is December, with an average of 9h and 24min of daylight.

How many hours of daylight does Petersburg have in December?

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

When is the sunrise / sunset in December in Petersburg?

In December, on the first day of the month, sunrise is at 7:02 am and sunset at 4:34 pm. On the last day of the month, in Petersburg, sunrise is at 7:21 am and sunset at 4:44 pm CST.

How long on average sun shines in December in Petersburg?

In Petersburg, Illinois, the average sunshine duration in December is 4.5h.

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

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 Petersburg?

In Petersburg, the average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a low health risk from unsafe 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
Petersburg, IL

Average temperature in December - Petersburg, IL
  • Average high temperature in December: 38.5°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 (32.9°F).

  • Average low temperature in December: 27.5°F

The month with the highest average low temperature is July (66°F).
The coldest month (with the lowest average low temperature) is January (20.7°F).

Average pressure in December
Petersburg, IL

Average pressure in December - Petersburg, 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).

Average wind speed in December
Petersburg, IL

Average wind speed in December - Petersburg, IL
  • Average wind speed in December: 9.7mph

The windiest months (with the highest average wind speed) are January, February and April (10.3mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).

Average humidity in December
Petersburg, IL

Average humidity in December - Petersburg, 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%).

Average rainfall in December
Petersburg, IL

Average rainfall in December - Petersburg, IL
  • Average rainfall in December: 1.5"

The wettest month (with the highest rainfall) is May (3.82").
The driest month (with the least rainfall) is December (1.5").

Average rainfall days in December
Petersburg, IL

Average rainfall days in December - Petersburg, IL
  • Average rainfall days in December: 8.1 days

The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is February (6.2 days).

Average snowfall in December
Petersburg, IL

Average snowfall in December - Petersburg, IL
  • Average snowfall in December: 1.46"

The month with the highest snowfall is January (4.02").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
Petersburg, IL

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

The month with the highest number of snowfall days is January (10.3 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
Petersburg, IL

Average daylight in December / Average sunshine in December - Petersburg, 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 3min

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 6min).

Average sunshine days in December
Petersburg, IL

Average sunshine days in December - Petersburg, IL
  • Average sunshine days in December: 18.1 days

The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is May (11.3 days).

Average UV index in December
Petersburg, IL

Average UV index in December - Petersburg, 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
Petersburg, IL

Average cloud cover in December - Petersburg, IL
  • Average cloud cover in December: 52

The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 30).

Average visibility in December
Petersburg, IL

Average visibility in December - Petersburg, 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).

Petersburg, Illinois, USA

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