August was Cool and Dry in Illinois

[September 18, 2017]    The statewide average temperature in August was 70.6 degrees, 3 degrees below normal. This was the 12th coolest August on record, according to Illinois State Climatologist Jim Angel at the Illinois State Water Survey, University of Illinois. This followed June and July which were both slightly above normal.

The warmest daily temperature in Illinois for August was 96 degrees, reported at Effingham on August 21. The coolest daily temperature in Illinois was 42 degrees, reported at Shabbona in DeKalb County on August 25.

The statewide average precipitation was 2.41 inches, 1.18 inches below normal. There was a narrow band with 3 to 6 inches of rainfall between Quincy to just north of Champaign. The rest of the state received 1 to 3 inches of rain, which was 1 to 3 inches below normal.

The highest monthly precipitation total for August was 7.09 inches, reported at both Augusta and Hoopeston.

The statewide average temperature for the summer was 73.1 degrees, 0.5 degrees below normal. The statewide average precipitation was 10.18 inches, 1.69 inches below normal. Much of the Midwest experienced a fairly wet summer. The only large dry spots were in Iowa and Illinois, and smaller areas with dry spots were in northern Minnesota and southern Michigan.

The National Weather Service outlook for September shows a continuation of August’s weather. Illinois and much of the eastern half of the U.S. have an increased chance of cooler than normal weather. Most of Illinois has an increased chance of being dry, as does most of the western half of the Midwest and the Plains states. Far southeastern Illinois has an increased chance of wetter than normal conditions.

[Lisa A. Sheppard]