Using historical data across Illinois, the driest June 15–July 18 period occurred in 1936 with only 1.32 inches of rainfall, followed by 1988 (1.63 inches), 1966 (1.76 inches), 2002 (1.87 inches), and 1914 (1.99 inches). For 30 and 60 days beyond the July 18 date, rainfall continued to be below normal in 1936, 1988, and 1966. There was a slow recovery in 1914 after 36 percent of normal rainfall within 30 days and 102 percent of normal rainfall within 60 days. “We still need to wait and see what happens in 2002,” says Angel.

Latest soil moisture measurements for Illinois (http://www.sws.uiuc.edu/warm/) show considerable drying in the top 20 inches across most of Illinois. As a result, soil moisture in this layer is below to well below normal. There are some exceptions in southern, western, and northeastern Illinois, where some areas have received scattered but substantial rainfall. Soil moisture statewide in the 40- to 72-inch layer is considerably higher, reflecting the above normal rainfall that occurred during May and early June. Root systems of crops planted early in the season are better developed and can take advantage of this deeper moisture. Later plantings of corn and soybeans are struggling.

To monitor these hot, dry summer conditions, the Illinois State Water Survey has developed a new Web page (http://www.sws.uiuc.edu/atmos/statecli/Summer2002/dry2002.htm) that includes tables and maps of precipitation and temperature, their departures from normal, and ranking of statewide precipitation since June 15, 2002. This information is updated automatically each day by 10 a.m. Additional information on conditions across the Midwest this summer can be found on the Midwestern Regional Climate Center Web site (http://mrcc.isws.illinois.edu/Watch/Drought/moisture.htm).