National Weather Service United States Department of Commerce

We still have a few more days of pleasant weather, before temperatures turn sharply cooler toward the end of the week. Expect highs in the 70s through Thursday, but after that, 50s will be more common on Friday and Saturday. Rain chances remain minimal, mainly limted to areas near and north of I-74 Wednesday night, but even then, chances are only around 20%.
With significantly cooler weather expected late this week, the threat of widespread frost is high. Freezing temperatures are also possible over a large part of central Illinois. Gardeners should monitor upcoming forecasts, and be prepared to protect sensitive vegetation if they want to extend the growing season.