Mount Vernon, IL has a humid subtropical climate with hot and muggy summers, cold winters, and mild springs and autumns. During the summer months, temperatures can reach into the mid to high 90s with oppressive humidity. The winter months feature cold temperatures that sometimes drop into the single digits or below zero. Spring is usually mild and pleasant, while autumn can bring colorful foliage and crisp air. Precipitation levels are average throughout the year, though heavier rain events do occur in the spring and summer months.
Mount Vernon, Illinois gets 44 inches of rain, on average, per year. The US average is 38 inches of rain per year.
Mount Vernon averages 11 inches of snow per year. The US average is 28 inches of snow per year.
On average, there are 207 sunny days per year in Mount Vernon. The US average is 205 sunny days.
Mount Vernon gets some kind of precipitation, on average, 101 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 87 degrees
Winter Low: the January low is 21
Rain: averages 44 inches of rain a year
Snow: averages 11 inches of snow a year