O'Fallon Weather in December

December in O'Fallon brings low temperatures, with daytime highs of 7°C (45°F) and nights around -3°C (27°F). Quite a bit of snow/rainfall is expected, around 95 mm (3.7 in), so pack an umbrella.

Rainfall in O'Fallon in December

Typically around 11 days of snow/rainfall are expected, averaging 95 mm (3.7 in) for the month. When it rains this month, it tends to come down fairly heavily. Showers can be substantial even if they don't last all day.

Temperature in O'Fallon in December

December in O'Fallon brings low temperatures, with highs of 7°C (45°F) and nights around -3°C (27°F). During December, you'll experience the winter season. Expect a cold feel throughout the day, not just in the mornings and evenings. Warm layers are essential. Nights are well below freezing at -3°C (27°F). An extra blanket is a good idea if you feel the cold, especially in older or less well-heated accommodation.

Sunshine in O'Fallon in December

The area enjoys a balanced 128 hours of sunlight, ensuring it's neither too overcast nor too sunny.

December in O'Fallon can still be great, but if you prefer pleasant temperatures along with dry and sunny conditions, our weather planner can help you explore other options in the world.

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Check the conditions for any month of the year.

• January
• February
• March
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• May
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• August

• September
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• December

For a detailed overview over the year and the best time to visit the United States of America, check out our O'Fallon's climate page.

O'Fallon Temperature in December

Min Temperature -3°C (27°F)  

Max Temperature 7°C (45°F)  

Chance of Rain 35%  

Precipitation 95 mm (3.7 in)  

Rainy days 11 days  

Humidity 74% *  

Sunshine 128 hours *  

Percentage Sunshine 44% *  

* Data from: St. Louis, the United States of America (48 KM, 29 Miles).

What to Wear in O'Fallon in December

Cold weather calls for smart layering in December. A thermal base layer makes a huge difference in staying warm. Add a wool sweater or fleece, then a wind-resistant outer jacket. Prepare for significant rainfall with proper waterproof clothing and shoes. Bring sunglasses since you'll have some sunny periods throughout the month

What To Do in O'Fallon in December

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

5/10

Cycling

4/10

Walking

4/10

Camping

1/10

Outdoor sports

4/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit the United States of America, check out our O'Fallon's climate page.

More climate data for O'Fallon

Temperature Rainfall Sunshine Humidity

See the full O'Fallon climate overview or explore weather in the United States of America.