O'Fallon Weather in August

August in O'Fallon brings very high temperatures, with daytime highs of 31°C (88°F) and nights around 19°C (66°F). Quite a bit of rainfall is expected, around 80 mm (3.1 in), so pack an umbrella.

Rainfall in O'Fallon in August

Rain is expected on roughly 9 days, totalling around 80 mm (3.1 in) for the month. Individual showers can be quite heavy this month. A proper umbrella or rain jacket is worth having.

Temperature in O'Fallon in August

August in O'Fallon brings very high temperatures, with highs of 31°C (88°F) and nights around 19°C (66°F). If you're spending a lot of time outdoors, it helps to plan around the warmer part of the day. At 19°C (66°F) overnight, it can feel quite a bit cooler after dark. Worth packing something warmer for evenings, but the cooler temperatures are ideal for sleeping.

Sunshine in O'Fallon in August

There are approximately 268 hours of sunshine this month, resulting in mostly clear days.

Should you favor a climate that's both dry and comfortably warm, October typically offers the most agreeable circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.

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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 August

Min Temperature 19°C (66°F)  

Max Temperature 31°C (88°F)  

Chance of Rain 29%  

Precipitation 80 mm (3.1 in)  

Rainy days 9 days  

Humidity 70% *  

Sunshine 268 hours *  

Percentage Sunshine 64% *  

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

What to Wear in O'Fallon in August

Warm but pleasant conditions in O'Fallon in August. Focus on lightweight, maybe with natural fabrics, cotton blend shirts, comfortable shorts, and breathable footwear. A light cover-up for sun protection is smart too. Wet weather is likely, so pack waterproof gear for multiple rainy days. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.

What To Do in O'Fallon in August

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

Swimming

9/10

Cycling

7/10

Walking

7/10

Camping

8/10

Outdoor sports

7/10

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.