State College, Pa. -- 4 October 2010 -- AccuWeather.com reports autumn kicked in full swing across the Midwest this weekend, as the coldest air of the season invaded the region.

Midwesterners have been waking up to frost and freezing temperatures over the past few days. Another round is in store for areas from Iowa and Missouri to Wisconsin and Michigan Tuesday morning.

Parts of the interior Southeast, including portions of Kentucky and Tennessee, will also be affected.

Lows tonight will dip near or below freezing across northern parts of Michigan and Wisconsin. While areas farther south will not get quite that chilly, it will be cold enough for frost to form under clear skies.

People in St. Louis and Cape Girardeau, Mo., Madison, Wis., and some northern and western suburbs of Chicago and Indianapolis may want to allow extra time to scrape frost off their windows Tuesday morning if their vehicles are not parked in a garage.

Sensitive outdoor plants and vegetables will also need to be protected again tonight.

For the Upper Midwest, the first frost has been right on time. For the lower Midwest and interior Southeast, however, it is a bit premature. Typically, these areas do not get their first frost until middle or late October.

For most places across the Midwest, the threat of frost and freezing temperatures will end after Tuesday morning.

However, areas from southeastern Missouri into Tennessee and Kentucky could endure one more round Tuesday night into Wednesday morning.

If you have questions or want to speak to a meteorologist, contact: 

Roberti@AccuWeather.com