I'm flying into Ohare on Sunday and will be transported up to Vernon Hills for a couple of days. I'm on business so there won't be any time for much of anything but, working, eating, and sleeping. My concern is that being from Florida and never really experiencing cold weather, I need advice on what cloths to bring. I'm used to warm climates as I avoid the cold whenever possible. I'll be inside 99% of the time but, I might have to be outside waiting for rides or maybe walking to somewhere to grab a drink or eat.

Should I bring full winter gear or can I get by with semi-warm stuff and just a heavy jacket? I really don't know how people up your way dress on the average cold day. Can you guys school this Florida boy on how not to freeze to death?

I suppose it depends on what your cold tolerance is, and what you think qualifies as a heavy jacket.  Sunday is supposed to be the coldest day of the three, with nighttime lows in the teens.  It's actually supposed to warm up to around 40 on Tuesday, which will be the warmest we've seen in weeks.  

If you're going to be indoors 99% of the time, you should be fine with normal indoor clothes.  Going to and from a car or shuttle bus might be cold for you, but the driver should have the heat going.  Wait for your car indoors.

If you are going to walk somewhere, well, then you probably will hate being out in the cold, even with your warmest clothes, but if you have to do that just wear layers.  T-shirt, long-sleeved shirt/sweater, jacket.  Gloves or pockets for your hands and something to cover your ears or head will go a long way towards keeping you feeling warmer.

A nice thin base layer might help keep the chills off. Discreet and easy to wear under business clothes.

Good advise, thanks! I have those things covered.

Yep. Got a couple of them to take. I figure if I get too hot indoors I can always pull off the base layer and shove it in my pack.

Vernon Hills has a shopping mall and the rest is just strip malls.  You aren't going to be walking outside other than maybe across a parking lot.  Unless it's windy, a jacket and hat will be fine.

Cold tolerance is a definite factor, I will frequently not bother to put on a jacket and walk around my property in a t-shirt in the winter if I am only planning to be out for just a few minutes and I am amazed whenever I head south in the spring or fall and the hotels are like, "Sorry our pool is closed because this 80 degree weather is too cold" and people are wearing coats.