O'Fallon Weather in May

In O'Fallon, May brings high daytime temperatures around 25°C (77°F), with nights cooling to 13°C (55°F). Expect quite a bit of rainfall this month.

Rainfall in O'Fallon in May

Rain is expected on roughly 14 days, totalling around 117 mm (4.6 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 May

In May, O'Fallon sees high temperatures, with highs of 25°C (77°F). Nights drop to around 13°C (55°F). This kind of day-to-night contrast is typical for this time of year. Nights drop to around 13°C (55°F), which is noticeably cooler than the daytime. A light jacket for the evening is a sensible addition, and the cool nights tend to make sleeping comfortable.

Sunshine in O'Fallon in May

There are approximately 269 hours of sunshine this month, resulting in mostly clear days.

If you prefer enjoying temperate temperatures and rain-free days, October typically offers 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.