O'Fallon Weather in May
May in O'Fallon averages 25°C (77°F) during the day and 14°C (57°F) at night. Quite a bit of rainfall is typical this month, with around 129 mm (5.1 in) on average. An umbrella is a good idea.
Rainfall in O'Fallon in May
You can expect rain on roughly 14 days based on historical data, averaging 129 mm (5.1 in) for the month. The rain this month tends to fall in heavier spells rather than light drizzle. When it rains, showers can be significant.
Temperature in O'Fallon in May
In May, O'Fallon sees high temperatures, with highs of 25°C (77°F). Nights drop to around 14°C (57°F). This kind of day-to-night contrast is typical for this time of year. Nights cool down to 14°C (57°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.
Sunshine in O'Fallon in May
The days are predominantly sunny, with an estimated total of around 269 hours of sunshine. These sun-filled days are perfect for playing sports, visiting parks, or going for a bike ride.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.
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
14°C (57°F)
Max Temperature
25°C (77°F)
Chance of Rain
47%
Precipitation
129 mm (5.1 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
Comfortable temperatures call for an easy wardrobe in May. Pack summer basics like t-shirts and shorts, but include a light jacket for cooler moments. A pair of comfortable walking shoes is essential. Expect heavy rainfall, so bring good rain protection and waterproof bags. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.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.
