Jefferson, MO County has a humid continental climate with hot summers and cold winters. The area experiences precipitation throughout the year, with average annual precipitation of 39.3 inches. The county's highest monthly average temperatures occur in July at 88°F (31°C), and its lowest in January at 26°F (-3°C). Snowfall is common during the winter months, with an average of 12.9 inches of snow per year. In general, spring and summer tend to bring more pleasant weather while fall and winter can be cold and damp.
Jefferson County, Missouri gets 43 inches of rain, on average, per year. The US average is 38 inches of rain per year.
Jefferson County averages 12 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 Jefferson County. The US average is 205 sunny days.
Jefferson County gets some kind of precipitation, on average, 99 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 22
Rain: averages 43 inches of rain a year
Snow: averages 12 inches of snow a year