Based on preliminary data, the statewide average temperature for the first half of June was 73.4 degrees, 3.3 degrees above normal.
The statewide average rainfall for the first half of June was 3.85 inches, 1.78 inches above normal. Much of the southern and northern thirds of the state were near normal while central Illinois was much above normal.
The wettest areas are in a region between Quincy and the Quad Cities (again) and in east-central Illinois. For June 1-15, the following rainfall totals were reported: Moline with 4.35 inches, Quincy with 4.78 inches, Springfield with 3.85 inches, Champaign with 4.88 inches , and a CoCoRaHS observer in Sidney (SE of Champaign) with 7.84 inches.
The National Weather Service provides a high-resolution precipitation product that combines both rain gauge and radar data. It can be found at http://water.weather.gov/precip/. Here is the rainfall departure map for June 1-15, 2010, clearly showing the heavy rain areas in western and east-central Illinois.
More rains are falling in Illinois while this is being written on the afternoon of June 15.