July Conditions in Illinois Ranged from Floods to Drought, Illinois State Water Survey

ISWS Press Release

For Immediate Release August 2, 2017
July Conditions in Illinois Ranged from Floods to Drought
Jim Angel, Ph.D. - (217) 333-0729, jimangel@illinois.edu
Lisa Sheppard - (217) 244-7270, sheppard@illinois.edu

CHAMPAIGN, Ill. - Northern Illinois experienced heavy rain and widespread flooding in July. Meanwhile, parts of central and southern Illinois experienced dry weather that caused crop damage, according to Illinois State Climatologist Jim Angel of the Illinois State Water Survey at the University of Illinois.

Central Illinois Sunset

On average, however, the statewide precipitation was 4.81 inches, which is 0.73 inches above normal.

In the northwestern part of the state, the average precipitation for July was 7.83 inches, and the third wettest July on record. The average wettest July on record was in 1902 with 9.21 inches.

The northeast experienced an average of 7.55 inches, and also the third wettest July on record for that region. Again, the number one year for the wettest July on record was in 1902.

Three of the highest monthly precipitation totals for July in Illinois were Cary (McHenry County) with 13.34 inches, Gurnee (Lake County) with 13.21 inches, and Chadwick (Carroll County) with 13.15 inches.

On the other extreme, some areas in western and southwestern Illinois were very dry with precipitation amounts of less than 2 inches. The lowest monthly total was at Quincy Dam with 0.68 inches.

The statewide average temperature for July was 76.1 degrees, 0.7 degrees above normal. Several stretches occurred with two to five days of hot, humid weather. However, these conditions were often interrupted by periods with slightly cooler, drier air as cold fronts swept across the state.

As is often the case in Illinois in summer, the hottest readings occurred in places that were dry. Locations that reported 100 degrees or higher included Jerseyville with 102 degrees, and three locations, Pittsfield, Effingham, and Belleville, with 100 degrees.


The Illinois State Water Survey at the University of Illinois at Urbana-Champaign, a division of the Prairie Research Institute, is the primary agency in Illinois concerned with water and atmospheric resources.

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