Monthly weather forecast and climate
O'Fallon, MO

What is the coldest month in O'Fallon?

With an average high-temperature of 37.9°F (3.3°C) and an average low-temperature of 18°F (-7.8°C), January is the coldest month in O'Fallon.

How much does it rain in O'Fallon?

Throughout the year, in O'Fallon, Missouri, 38.6" (981.4mm) of rain is accumulated.

What is the driest month in O'Fallon?

January is the month with the least rainfall in O'Fallon, with 1.8" (45.5mm) of accumulated precipitation.

What is the rainiest month in O'Fallon?

The month with the most rainfall is May when 4.3" (110.2mm) of precipitation is typically aggregated.

What is the warmest month in O'Fallon?

July is the warmest month, with an average high-temperature of 88°F (31.1°C) and an average low-temperature of 68°F (20°C).
Average rainfall - O
Average daylight - O

The month with the longest days is June (Average daylight: 14.9h).
The month with shortest days is December (Average daylight: 9.5h).