The US Drought Monitor report, released yesterday, expanded the “abnormally dry” area across much of central and northern Illinois (first figure). This was based on precipitation totals in the last 30-60 days. For example, the last 30 days were significantly short on precipitation for much of the state (second figure).
The US Drought Monitor uses the “abnormally dry” category as an early warning for the potential for drought. It is usually a period with noticeably lower precipitation but without any significant impacts, at least yet. Fortunately, the cooler than average temperatures have prevented a lot of stress on crops at this time.