Orb weaver species seem to be frequently seen in this area. However I’ve never seen any wild spider this colorful in the state of Wisconsin.
I’m inclined to guess Araneus trifolium, the Shamrock Orb-weaver. It comes in a wide variety of colors but will always have light-colored leg bands, as your specimen has. Is it just the lighting, or does the abdomen look a bit shriveled? If so, this spider may be dehydrated or may be a female post egg-laying.