This is probably not an issue for most because many new parents buy blankets made to attach to and cover a car seat. My husband and I took many walks this Spring with our April baby in the stroller and we clipped a regular blanket to the car seat handle.
I worried that she would still be hot in the Charlotte sun and it took me weeks to figure out a better way to drape the blanket so Julia would get a breeze. Instead of draping over the car seat by her feet, we began draping from the top of the car seat to the stroller handles. This seems simple but I wish we’d thought of it sooner so our little bun could have stopped baking on her birthday.