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.
Check the conditions for any month of the year.
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 May
Min Temperature
13°C (55°F)
Max Temperature
25°C (77°F)
Chance of Rain
47%
Precipitation
117 mm (4.6 in)
Rainy days
14 days
Humidity
65% *
Sunshine
269 hours *
Percentage Sunshine
60% *
Best Places in the United States of America in May
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in May →
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What to Wear in O'Fallon in May
For O'Fallon in May, you'll want flexible clothing. It's wise to pack cotton shirts, comfortable shorts, and a pair of jeans for cooler evenings. A light sweater or jacket is useful for air-conditioned spaces (like buses) or unexpected cool moments. High rain levels are expected, so pack waterproof gear and an umbrella or poncho. You'll definitely want to pack sunglasses and sunscreen. There will be plenty of bright sunshine this month.What To Do in O'Fallon in May
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
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.
Temperature Rainfall Sunshine Humidity
See the full O'Fallon climate overview or explore weather in the United States of America.
