If your soil is workable, you can plant now. You can get some foliar damage from any hard frosts still in the future, but the plant itself should be fine, specially as clems should be planted quite deeply.

How large is this new plant? I generally grow on small clematis plants for a season or so in a gallon pot until the root system has developed enough to fill the pot. This just gives the vines a head start on proper establishment. A young/small clematis planted in a gallon container now should be sufficiently well developed enough to plant out in the garden by late summer/early fall.

Hi gardengal!
Yes, my soil is workable, and this clem is not in a gallon pot. I would say the pot is about a quart. I've attached a pic.

Since it's been inside for a week now, I would give it a bit of shade from a lawn chair or something while it gets used to being outside for a few days to a week so that it doesn't get sunburned. If there is a frost, you can always throw a blanket over the chair.

It is of course your choice what to do now, but if this were my vine, I'd repot into a gallon sized container and grow it on for the season before planting out in the garden. Young, small clems are just very vulnerable to all sort of issues if planted directly into the ground, not the least of which is stem breakage from any variety of unhappy occurrences. Or being overwhelmed by larger, more established plants. I'd also cut the vine back by at least half.

I realize this delays any enjoyment you may have from this vine near term but as clems seldom come into their own until after 3-5 years in the ground and then can live and flower for decades, it makes sense to give it as good a start as possible.

Regardless of whether you pot it up or plant directly, make sure you plant the vine deeply, about 4" deeper than it is in its current pot. This will encourage a stronger, better developed root system and encourage additional shooting from the root crown. More shoots = stronger plant with greater flowering potential.

I'm not sure what it's like in Chicago right now but in Des Moines but we have had abnormally warm weather here and my clematis from previous years are already coming up and growing, so I think it's safe enough! I just planted The President clematis yesterday, he had grown about a foot in 2 weeks from a bareroot and was getting leggy from growing under my grow lights. I did cut him down to about 6 inches like gardengal had mentioned. They usually shoot back up quickly.

If you plant it directly into the ground (which is what I myself like to do) I recommend putting a ring of chicken wire around it. It helps prevent all those unhappy incidents gardengal speaks of.. especially rabbits chomping on the leaves.

Anyways, best of luck! And I hope you share some pictures when it blooms! :)

I would wait until after May 1st to plant it. The weather is still iffy around this time of year. Remember there are two seasons in Chicago - Winter season and construction season! LOL. I'm from there myself.