Eureka, IL has a humid continental climate with mild winters and warm summers. The average annual temperature in the area is approximately 52°F (11°C), and the coldest temperatures in winter are usually around 18°F (-8°C). During the summer months, temperatures can reach as high as 90°F (32°C). The area receives an average of 39 inches (99 cm) of precipitation annually, primarily in the form of rain during spring and fall. Snowfall is also common during the winter months, but it rarely accumulates more than a few inches on the ground.
Eureka, Illinois gets 39 inches of rain, on average, per year. The US average is 38 inches of rain per year.
Eureka averages 23 inches of snow per year. The US average is 28 inches of snow per year.
On average, there are 189 sunny days per year in Eureka. The US average is 205 sunny days.
Eureka gets some kind of precipitation, on average, 108 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 86 degrees
Winter Low: the January low is 15
Rain: averages 39 inches of rain a year
Snow: averages 23 inches of snow a year