O'Fallon Weather in July

July in O'Fallon brings very high temperatures, with highs of 31°C (88°F) and nights dropping to 20°C (68°F). Rainfall is on the higher side this month, averaging around 105 mm (4.1 in), so keep a rain jacket handy.

Rainfall in O'Fallon in July

You can expect rain on around 10 days based on historical patterns, with 105 mm (4.1 in) average 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 July

Daytime temperatures in O'Fallon reach 31°C (88°F) in July, dropping to 20°C (68°F) at night. The hottest part of the day is usually in the afternoon, so lighter clothing can help you stay comfortable. Nights cool down to 20°C (68°F), so a light jacket or extra layer is useful once the sun goes down. On the plus side, the cooler nights make for comfortable sleeping conditions. Expect some days to be hotter than these averages. Stay cool by wearing light clothing and drinking plenty of water throughout the day.

Sunshine in O'Fallon in July

With approximately 311 hours of sunshine, the days are filled with clear skies. It makes it a perfect month for being outside.

For O'Fallon itself, October generally stands out with the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.