St. Clair, IL County has a humid continental climate with hot summers and cold winters. The average temperature in the summer months is around 79°F and the average winter temperature is about 34°F. Precipitation is relatively evenly distributed throughout the year, with an average of around 39 inches per year. Snowfall can be quite heavy during winter months, when temperatures plunge below freezing point. The weather in St Clair County is generally pleasant for most of the year, making it a great destination for outdoor activities like camping and hiking.
St. Clair County, Illinois gets 42 inches of rain, on average, per year. The US average is 38 inches of rain per year.
St. Clair 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. Clair County. The US average is 205 sunny days.
St. Clair 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 89 degrees
Winter Low: the January low is 22
Rain: averages 42 inches of rain a year
Snow: averages 13 inches of snow a year