Naperville, IL, gets 36 inches of rain per year. The US average is 37. Snowfall is 33 inches. The average US city gets 25 inches of snow per year. The number of days with any measurable precipitation is 109.
On average, there are 189 sunny days per year in Naperville, IL. The July high is around 86 degrees. The January low is 14. Our comfort index, which is based on humidity during the hot months, is a 43 out of 100, where higher is more comfortable. The US average on the comfort index is 44.