Washington, IL County has a humid continental climate with warm, humid summers and cold, snowy winters. Average monthly temperatures range from 27°F (-3°C) in January to 73°F (23°C) in July. Annual precipitation averages just over 41 inches (1,041 mm), with the wettest months being April through September. While Washington County experiences all four traditional seasons, snowfall can vary significantly from year to year. Cold winter winds blow out of the northwest and flooding is not uncommon during spring thaws. Summers are often hot and humid with occasional thunderstorms.
Washington County, Illinois gets 43 inches of rain, on average, per year. The US average is 38 inches of rain per year.
Washington County averages 11 inches of snow per year. The US average is 28 inches of snow per year.
On average, there are 205 sunny days per year in Washington County. The US average is 205 sunny days.
Washington County gets some kind of precipitation, on average, 100 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 43 inches of rain a year
Snow: averages 11 inches of snow a year