August should bring cooler temperatures according to Dr. Allen Staver, Northern Illinois University meteorologist. In fact, the end of August usually brings temperatures that are five degrees cooler than the beginning of the month. Six days can be expected to reach 90 degrees, but late August lows can go below 50. Precipitation is variable during August, ranging from a monthly total of one inch to as much as ten inches or more. The normal, around four inches, includes five thunderstorms during approximately eight days of rainfall for the month.
Flood producing amounts are rare.
On the average, only one day during August exceeds an inch of rainfall. August, September and October are the sunniest months of the year, but daylight is one hour shorter by the end of August. Stavers reports that the outlook for this August is for cooler than normal temperatures with average precipitation.