While there were a few cold stretches in April, the statewide average temperature for the month was 54.1 degrees, 1.7 degrees above average.
Precipitation in Illinois for April was more complicated. April precipitation was in the range of two to four inches in northern and central Illinois, and 4 to 7 inches in southern Illinois. As a result, the northern two-thirds of the state was slightly below average while the southern third was up to 2 inches above average. Fort Massac State Park reported the highest monthly precipitation total of 7.80 inches.
The Midwest had alternating bands of above and below-average precipitation for April. The above-average precipitation in southern Illinois extended into Indiana, Ohio, Kentucky and the rest of the Ohio River Valley. Just to the north, was a band of slightly below-average precipitation across Missouri, northern Illinois, northern Indiana, and parts of Michigan. Another band of wetter conditions extends from Kansas, Iowa, Wisconsin, and western Michigan. Drier than average conditions have prevailed for several months in Minnesota, and the Dakotas.
The USGS graph shows the discharge on the Ohio River at Metropolis, IL, during the exceptionally wet conditions in April all along the Ohio River Valley.