Seneca, IL has a humid continental climate. Summers are hot and humid, with average temperatures ranging between the mid 70s to low 80s Fahrenheit. Winters are cold, with moderate snowfall and temperatures usually near or below freezing. Spring and fall are mild but erratic due to the transitional climate between summer and winter. The yearly precipitation averages around 38 inches, mostly during spring months. Seneca has an average of 120 days of sunshine every year, making it an ideal spot for outdoor activities such as hiking in the nearby Shawnee National Forest or fishing in the Illinois River.
Seneca, Illinois gets 37 inches of rain, on average, per year. The US average is 38 inches of rain per year.
Seneca averages 23 inches of snow per year. The US average is 28 inches of snow per year.
On average, there are 190 sunny days per year in Seneca. The US average is 205 sunny days.
Seneca gets some kind of precipitation, on average, 114 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 84 degrees
Winter Low: the January low is 15
Rain: averages 37 inches of rain a year
Snow: averages 23 inches of snow a year