St. Charles, MO County has a humid continental climate, with cold winters and hot, humid summers. The average high temperature in January is 33°F, while the average high temperature in July usually reaches 86°F. Precipitation is fairly evenly distributed throughout the year, averaging around 47 inches per year. The area also experiences four distinct seasons and wide variation in temperature between day and night. Snowfall is relatively light compared to other parts of Missouri, averaging around 10 inches per year. Overall, St. Charles has a mild but changing climate that brings warm summer days as well as cold winter nights and occasional snowfall each season.
St. Charles County, Missouri gets 42 inches of rain, on average, per year. The US average is 38 inches of rain per year.
St. Charles County averages 13 inches of snow per year. The US average is 28 inches of snow per year.
On average, there are 202 sunny days per year in St. Charles County. The US average is 205 sunny days.
St. Charles County gets some kind of precipitation, on average, 106 days per year. Precipitation is rain, snow, sleet, or hail that falls to the ground. In order for precipitation to be counted you have to get at least .01 inches on the ground to measure.
Weather Highlights
Summer High: the July high is around 88 degrees
Winter Low: the January low is 21
Rain: averages 42 inches of rain a year
Snow: averages 13 inches of snow a year